JP2006202546A - Ion irradiation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion irradiation apparatus capable of achieving both of clean ion irradiation for an object to be irradiated and close monitoring of ion beams. <P>SOLUTION: The ion irradiation apparatus comprises: a beam scanner 82 having a function of deflecting an ion beam 30 that has been derived from an ion source 20 and passed through a mass separator 32 into two deflecting directions along an X direction and a function of scanning the ion beam along the X direction in each of the two deflecting directions; two beam collimators 86, 88 for bending back the ion beams derived from the beam scanner 82 to make parallel beams; a treatment chamber 90 to which the ion beams 30 derived from the beam collimator 86 are introduced and in which treatment such as ion injection is performed by applying the ion beams to the object to be irradiated 2; a driving mechanism 94 for mechanically driving the object 2 in a Y direction; and a measurement chamber 92 to which the ion beams 30 derived from the ion beam collimator 88 are introduced and in which only measurement of the ion beams is performed using a beam measuring instrument 96. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ion irradiation apparatus that irradiates an irradiation object (for example, a semiconductor substrate; the same applies hereinafter) with an ion beam and performs processing such as ion implantation.

  While having two processing chambers (terminal end stations) and performing ion implantation on the injection target in one processing chamber, it is possible to replace the injection target in the other processing chamber. Patent Document 1 describes an ion implantation apparatus that improves throughput (processing capacity per unit time).

  In the conventional ion implantation apparatus having two processing chambers as described above, although not explicitly disclosed in Patent Document 1, generally, a beam measuring instrument for measuring an ion beam is also provided in each of the two processing chambers. It was provided. That is, the two processing chambers both perform ion implantation and beam measurement, and have the same function. Conventionally, such two processing chambers have been provided to improve throughput. .

JP-A-56-48052 (page 4, upper right column, line 1-18, page 5, upper left column, line 9-same upper right column, line 3, FIG. 1)

  Since the conventional ion implantation apparatus as described above has a beam measuring instrument in each processing chamber, the structure around the ion implantation portion to the implanted object becomes complicated, thereby clean ions for the implanted object. There is a problem that it is impossible to achieve both the implantation and the strict monitoring of the ion beam.

  That is, in the conventional ion implantation apparatus as described above, when an ion beam is incident on the beam measuring instrument in the processing chamber, contaminants such as outgas are generated from the beam measuring instrument, and this occurs in the implanted material (more specifically, Is difficult to perform clean ion implantation because it adheres to the surface and contaminates the implanted material.

  In addition, the beam measuring instrument is complicated for the strict monitoring of the ion beam, and contaminants are more likely to be generated, so that clean ion implantation cannot be performed. Simplifying the beam instrumentation reduces the pollutants generated from them, but makes it impossible to monitor the ion beam closely.

  More specifically, for example, ion implantation is often used to form a semiconductor device on the surface of a semiconductor substrate, which is an object to be implanted. However, in recent years, miniaturization of this semiconductor device has been advanced. In such a case, contamination of the semiconductor substrate becomes a serious problem. This is because finer semiconductor devices are more likely to cause defects due to contaminants. Thereby, for example, the yield of semiconductor devices formed on the surface of the semiconductor substrate is reduced.

  In addition, with the miniaturization of the semiconductor device, the energy of the ion beam used for ion implantation is reduced (for example, about 5 keV or less), and the lower energy ion beam is likely to spread due to its space charge effect. Particularly in the case of a low-energy ion beam, the ion beam easily hits various places including the beam measuring instrument in the processing chamber to easily generate contaminants.

  Furthermore, since a low-energy ion beam is likely to spread due to the mutual repulsion of its charge, a strict monitoring of the ion beam is particularly necessary to achieve high-accuracy ion implantation. A measuring instrument is required, and if such a beam measuring instrument is provided in the processing chamber, contaminants are more likely to be generated from the beam measuring instrument.

  The problems as described above are not limited to an ion implantation apparatus that performs ion implantation on an object to be implanted. More generally, an ion beam is irradiated on an object to be irradiated (that is, ion irradiation is performed). It also exists in ion irradiation apparatuses that perform processing. Accordingly, the main object of the present invention is to provide an ion irradiation apparatus that can achieve both clean ion irradiation to an irradiation object and strict monitoring of an ion beam.

  The ion irradiation apparatus according to the present invention is derived from an ion source that extracts an ion beam, a mass separator that selects and derives a specific ion species from the ion beam extracted from the ion source, and the mass separator. Beam scanning having a function of deflecting an ion beam in the first and second deflection directions in the X direction, which is a predetermined direction, and a function of scanning the ion beam in the X direction in each of the first and second deflection directions A first beam collimator that converts the diverging ion beam derived from the beam scanner in the first deflection direction back into a parallel beam in the X direction, and the second from the beam scanner. A second beam collimator that bends the diverging ion beam derived in the deflection direction in the X direction into a parallel beam, and the first beam collimator. A chamber into which an ion beam derived from a collimator is introduced, and an irradiation object is introduced, and the irradiation object is irradiated with the ion beam to perform processing such as ion implantation; and A drive mechanism for mechanically driving the object to be irradiated in a Y-direction intersecting the X-direction in the irradiation region of the ion beam in the processing chamber, and an ion beam derived from the second beam collimator are introduced. And a measurement room that has a beam measuring device that measures the ion beam and that only measures the ion beam without performing processing on the irradiated object.

  According to the ion irradiation apparatus, the irradiation object is irradiated with an ion beam in the processing chamber to perform ion implantation and the like, and in the measurement chamber, the irradiation object is not processed and only the ion beam is measured. Since functional differentiation is achieved, it is possible to simplify the structure around the ion irradiation portion of the object to be irradiated in the processing chamber.

  As a result, it is possible to suppress the generation of contaminants when the ion beam is incident on the beam measuring instrument in the processing chamber, and to perform clean ion irradiation on the irradiation object.

  In addition, since a beam measuring instrument can be provided in the measurement room without worrying about contamination of the irradiated object, it is possible to monitor the ion beam closely.

  It is preferable that the vacuum container constituting the processing chamber and the vacuum container constituting the measurement chamber have substantially the same structure. Moreover, it is preferable that the positional relationship between the irradiation object in the irradiation state in the processing chamber and the ion beam and the positional relationship between the beam measuring device and the ion beam in the measurement chamber are substantially the same.

  Using an electromagnet having two pairs of magnetic poles, one of the magnetic poles of the pair constitutes the first beam collimator and the other pair of magnetic poles constitutes the second beam collimator. Anyway.

  The beam measuring device may measure at least one of a beam current, a cross-sectional dimension, a position, and a scanning width of the ion beam.

  You may further provide the controller which controls the ion beam which injects into the said process chamber using the measurement information from the said beam measuring device. Further, an acceleration / deceleration device for accelerating or decelerating the ion beam may be provided between the ion source and the beam scanner.

  According to the first aspect of the present invention, the irradiation object is irradiated with an ion beam in the processing chamber to perform processing such as ion implantation, and in the measurement chamber, the irradiation object is not processed and only the ion beam is measured. Since it is configured so as to perform functional differentiation, it is possible to achieve both clean ion irradiation to the irradiation object and strict monitoring of the ion beam.

  According to the second and third aspects of the invention, by adopting the above configuration, the physical environment (conditions) between the ion irradiation in the processing chamber and the ion beam measurement in the measurement chamber becomes closer. There is a further effect that the measurement accuracy of the ion beam used for irradiation can be further improved.

  According to the invention of claim 4, by adopting the electromagnet, it is possible to achieve a concrete realization of the coincidence between the ion irradiation and the strict monitor as well as simplifying the configuration of the ion irradiation apparatus. There is a further effect.

  According to the fifth aspect of the present invention, there is a further effect that various measurement of the ion beam can be performed as necessary by the beam measuring instrument.

  According to the sixth aspect of the invention, there is an additional effect that ion irradiation can be performed more accurately and more stably on the irradiated object using the measurement information from the beam measuring instrument.

  According to the seventh aspect of the invention, there is a further effect that ion beams with various energies can be obtained by the accelerometer.

  FIG. 1 is a schematic plan view showing an embodiment of an ion irradiation apparatus according to the present invention. In the following drawings, in order to show an example of the orientation of each device in the three-dimensional space, three axes orthogonal to each other at one point, that is, the X axis (for example, the horizontal axis), the Y axis (for example, the vertical axis) The Z axis (for example, the horizontal axis) is illustrated, and will be described with reference to these as necessary.

  The ion irradiation apparatus includes an ion source 20 that extracts an ion beam 30 and a mass separator 32 that selects and derives a specific ion species from the ion beam 30 extracted therefrom. Note that the path through which the ion beam 30 passes from the ion source 20 to the processing chamber 90 and the measurement chamber 92 described later is in a vacuum container (not shown) and is maintained in a vacuum atmosphere.

  The ion source 20 includes a plasma generation unit 22 that generates plasma by ionizing gas or vapor by arc discharge, high-frequency discharge, microwave discharge, or the like, and the plasma generation unit 22 (more specifically, from the plasma inside thereof). And an extraction electrode system 26 for extracting the ion beam 30 by the action of an electric field.

  In this example, the mass separator 32 is a mass separation electromagnet that selects and derives specific ion species by bending the ion beam 30 in the XZ plane by the magnetic field 46.

  In the vicinity of the downstream side of the outlet of the mass separator 32, a mass separation slit 52 that passes the specific ion species and blocks other ion species is preferably provided as in this example. If it does so, the said mass separation slit 52 and the mass separator 32 will cooperate, and the mass separation performance (mass resolution) of the ion beam 30 can be improved more.

  In addition, an acceleration / decelerator 80 that accelerates or decelerates the ion beam 30 between the ion source 20 and a beam scanner 82 described later, for example, between the mass separation slit 52 and the beam scanner 82 as in this example. May be provided. By doing so, it is possible to obtain the ion beam 30 having various energies from high energy (for example, several tens keV to several hundred keV) to low energy (for example, about 5 keV or less as described above). The accelerometer 80 is, for example, an electrostatic accelerometer that has a plurality of electrodes and accelerates or decelerates the ion beam by an electrostatic field.

  This ion irradiation apparatus is further derived from the mass separator 32, and in this example, the ion beam 30 that has passed through the mass separation slit 52 and the accelerator / decelerator 80 is transmitted in a predetermined direction, that is, the X direction, more specifically. In the X direction which is one direction in the beam deflection surface (that is, the XZ plane) in the mass separator 32, the first deflection direction (left direction indicated by a solid line in FIG. 1) and the second deflection direction (FIG. 1). A beam having a first function of deflecting in the right direction indicated by a two-dot chain line) and a second function of expanding (diverging) the ion beam 30 in the X direction by scanning in the X direction in each of the deflection directions. A scanner 82 is provided.

  By the first function, neutral particles traveling straight without being deflected by the electromagnetic field can be separated from the ion beam 30, and the ion beam is switched to enter a processing chamber 90 and a measurement chamber 92, which will be described later. Can do. The above-described deflection (switching) of the ion beam 30 by the first function may be performed each time one object 2 to be described later is processed, or a plurality of predetermined numbers (for example, one lot) of irradiation. It may be performed every time the object 2 is processed.

  By the second function, the ion beam 30 having a constant cross-sectional shape (for example, a cross-sectional shape elongated in the Y direction) incident on the beam scanner 82 is scanned in the X direction, and a wide area, more specifically, an object to be irradiated. The ion beam 30 can be irradiated to a region having a width equal to or greater than 2 in the X direction.

  The beam scanner 82, as shown in the figure, deflects and scans the ion beam 30 incident thereon symmetrically with respect to the incident axis 84, which simplifies the equipment configuration and improves the beam measurement accuracy. Although it is preferable from the viewpoint, it is not limited thereto.

  The beam scanner 82 includes an electromagnet having magnetic poles facing each other with a gap, and a power source for generating a DC magnetic field component for the first function and an AC magnetic field component for the second function in the electromagnet. It may be configured with. More specifically, this power source is a power source that outputs a current obtained by superimposing an alternating current on a direct current.

  Alternatively, the beam scanner 82 is a power source that generates electrodes that are opposed to each other with a gap therebetween, and a DC electric field component for the first function and an AC electric field component for the second function between the electrodes. It may be configured with. More specifically, this power source is a power source that outputs a voltage obtained by superimposing an AC voltage on a DC voltage.

  On the downstream side of the first deflection direction of the beam scanner 82, a diverging ion beam 30 derived from the beam scanner 82 in the first deflection direction is bent back in the X direction to be converted into a parallel beam. A beam collimator 86 is provided. In other words, the beam collimator 86 performs a parallel scan in the X direction of the ion beam 30 in cooperation with the beam scanner 82.

  The beam collimator 86 may be composed of, for example, an electromagnet similar to the sector magnet described in Patent Document 1, or a scan electrode pair as described in, for example, JP-A-4-22900. May be composed of electrode pairs to which voltages having a phase difference of 180 degrees are applied. The same applies to a second beam collimator 88 described later.

  On the downstream side of the second deflection direction of the beam scanner 82, a diverging ion beam 30 derived from the beam scanner 82 in the second deflection direction is bent back in the X direction to be converted into a parallel beam. A beam collimator 88 is provided. In other words, the beam collimator 88 performs a parallel scan in the X direction of the ion beam 30 in cooperation with the beam scanner 82.

  The first and second beam collimators 86 and 88 may be configured by using one electromagnet 110 as in the example shown in FIG. The electromagnet 110 has an iron core 112 having two pairs of magnetic poles 114 and 115 facing each other with a gap through which the ion beam 30 passes, and a coil 118 that excites it. Magnetic fields 116 and 117 in opposite directions are generated in the gap between the magnetic poles 114 and the gap between the magnetic poles 115, whereby the ion beam 30 is bent in the opposite directions. One pair of magnetic poles 114 constitutes the first beam collimator 86, and the other pair of magnetic poles 115 constitutes the second beam collimator 88. By doing in this way, the structure of an ion irradiation apparatus can be simplified and the consistency of ion irradiation and ion measurement can be aimed at.

  Further, the beam scanner 82 and the first and second beam collimators 86 and 88 may be constituted by one electromagnet.

  Referring to FIG. 1 again, downstream of the beam collimator 86 is a room into which the ion beam 30 led out from the beam collimator 86 is introduced, and an object to be irradiated (for example, a semiconductor substrate) 2 is present. A processing chamber 90 is provided which is introduced and performs ion irradiation by irradiating the irradiation object 2 with the ion beam 30.

  In the processing chamber 90, a holder 14 for holding the irradiated object 2 is provided. In the ion irradiation apparatus, the irradiation object 2 held by the holder 14 in the processing chamber 90 intersects the X direction in the irradiation region of the ion beam 30 (for example, the Y direction substantially orthogonal to the X direction). ) Has a drive mechanism 94 that mechanically reciprocates. In the example of FIGS. 1 and 2, the drive mechanism 94 is provided below or below the processing chamber 90 (back side of the paper surface) as an example. By the driving of the irradiation object 2 and the scanning of the ion beam 30 (that is, hybrid scanning), the entire surface of the irradiation object 2 can be irradiated with the ion beam 30 to perform processing such as ion implantation.

  On the downstream side of the beam collimator 88, there is a chamber into which the ion beam 30 derived from the beam collimator 88 is introduced, and a beam measuring device 96 that measures the ion beam 30. There is provided a measurement chamber 92 that performs only the measurement of the ion beam 30 without performing ion irradiation on the. The measurement chamber 92 and the processing chamber 90 are different from each other (in other words, separated from each other).

  In this example, the beam measuring instrument 96 measures the beam current, the cross-sectional dimension, the position, and the scanning width of the ion beam 30, but is not limited thereto, and measures at least one of them. Things can be used. By providing such a beam measuring device 96, various measurements of the ion beam 30 can be performed as necessary.

  According to the ion irradiation apparatus, the irradiation object 2 is irradiated with the ion beam 30 in the processing chamber 90 to perform processes such as ion implantation, and the measurement chamber 92 performs the ion beam measurement without performing the processing on the irradiation object 2. Therefore, it is possible to simplify the structure around the ion irradiation portion of the object to be irradiated 2 in the processing chamber 90.

  As a result, it is possible to suppress the generation of contaminants by the ion beam 30 entering the beam measuring instrument in the processing chamber 90 and perform a clean ion irradiation process on the irradiated object 2. For example, as described above, the irradiated object 2 is a semiconductor substrate (for example, a silicon substrate), and the surface of the semiconductor substrate is finely irradiated by irradiating the surface with a low-energy ion beam 30 to perform ion implantation. This is particularly noticeable when forming a simple semiconductor device. For example, the yield of semiconductor devices formed on the semiconductor substrate surface can be improved.

  On the other hand, since the beam measuring device 96 can be provided in the measurement chamber 92 without worrying about contamination of the irradiated object 2, the ion beam 30 can be monitored closely. That is, in order to perform strict monitoring of the ion beam 30, for example, even if a complicated or various beam measuring device 96 is provided in the measurement chamber 92, the processing chamber 90 and the measurement chamber 92 are separate from each other and the measurement is performed. Even if a pollutant is generated in the chamber 92, it does not contaminate the irradiated object 2 in the processing chamber 90. Therefore, the beam measuring device 96 as described above is provided freely from the standpoint of improving measurement accuracy. Can do.

  As a result, it is possible to achieve both clean ion irradiation to the irradiation object 2 and strict monitoring of the ion beam 30.

  Note that, as in the example shown in FIG. 2, secondary electrons generated when the ion beam 30 enters the beam measuring instrument 96 in the vicinity of the upstream side of the beam measuring instrument 96 are prevented from leaking out of the measurement system. A secondary electron suppression electrode 98 may be provided. Thereby, the measurement of the ion beam 30 by the beam measuring instrument 96 can be made more accurate. The secondary electron suppression electrode 98 and the secondary electron suppression electrode 100 described later have, for example, a cylindrical shape, and a negative voltage is applied from a power source (not shown).

  Further, although the processing chamber 90 mainly performs ion irradiation processing on the irradiation object 2, a necessary minimum measuring instrument and related devices may be provided inside. For example, as in the example shown in FIG. 2, the secondary electron generated from the beam current measuring instrument 102 that measures the beam current of the ion beam 30 at the time of ion irradiation to the irradiation object 2, the beam current measuring instrument 102, and the like. May be provided with a secondary electron suppression electrode 100 that suppresses leakage of the liquid from the measurement system. Based on the measurement information from the beam current measuring instrument 102, the control mechanism 104 can control the drive mechanism 94 to control the mechanical drive speed of the irradiation object 2.

  Further, by using the measurement information from the beam measuring device 96, for example, by controlling the beam scanner 82, the ion beam 30 incident on the processing chamber 90 is controlled, and irradiation control for the irradiation object 2 is performed. Although the control apparatus 106 may be provided, it is not limited to this, and it does not prevent other devices from being controlled. Thereby, it becomes possible to perform ion irradiation more accurately and more stably on the irradiation object 2 using the measurement information of the beam measuring instrument 96.

  It is preferable that the vacuum vessel 91 constituting the processing chamber 90 and the vacuum vessel 93 constituting the measurement chamber 92 have substantially the same structure. As a result, the physical environment (conditions) between the ion irradiation in the processing chamber 90 and the ion beam measurement in the measurement chamber 92 becomes closer, so that the measurement accuracy of the ion beam 30 used for ion irradiation can be further improved. Can do.

  Further, the positional relationship between the irradiation object 2 in the irradiation state in the processing chamber 90 and the ion beam 30 and the positional relationship between the beam measuring device 96 and the ion beam 30 in the measurement chamber 92 are substantially the same. It is preferable to keep it. For example, the surface of the irradiation object 2 in the irradiation state in the processing chamber 90 and the surface of the beam measuring instrument 96 in the measurement chamber 92 are positioned on the same or substantially the same plane 97 (see FIG. 1). Is preferred. Also in this case, since the physical environment (conditions) between the ion irradiation in the processing chamber 90 and the ion beam measurement in the measurement chamber 92 becomes closer, the measurement accuracy of the ion beam 30 used for ion irradiation is further improved. be able to.

It is a schematic plan view which shows one Embodiment of the ion irradiation apparatus which concerns on this invention. FIG. 2 is a plan view showing the processing chamber and the measurement chamber in FIG. 1 in more detail. It is a schematic longitudinal cross-sectional view which shows an example of the electromagnet which comprises the 1st and 2nd beam collimator.

Explanation of symbols

2 Irradiated object 20 Ion source 30 Ion beam 32 Mass separator 80 Accelerator / decelerator 82 Beam scanner 86 First beam collimator 88 Second beam collimator 90 Processing chamber 92 Measurement chamber 94 Drive mechanism 96 Beam measurement Device 106 Controller 110 Electromagnet

Claims (7)

An ion source for extracting an ion beam;
A mass separator that selects and derives a specific ion species from an ion beam extracted from the ion source;
The function of deflecting the ion beam derived from the mass separator in the first and second deflection directions in the X direction, which is a predetermined direction, and the ion beam in each of the first and second deflection directions. A beam scanner having a function of scanning
A first beam collimator for bending the diverging ion beam derived from the beam scanner in the first deflection direction back into a parallel beam in the X direction;
A second beam collimator for bending the diverging ion beam derived from the beam scanner in the second deflection direction back into a parallel beam in the X direction;
A room in which an ion beam derived from the first beam collimator is introduced, and an object to be irradiated is introduced, and the object is irradiated with the ion beam to perform processing such as ion implantation. Room,
A drive mechanism that mechanically drives the object to be irradiated in the Y direction intersecting the X direction in the irradiation region of the ion beam in the processing chamber;
A room into which an ion beam derived from the second beam collimator is introduced, and has a beam measuring device for measuring the ion beam, and measures the ion beam without performing processing on the irradiation object. An ion irradiation apparatus comprising a measurement chamber that performs only the measurement.   The ion irradiation apparatus according to claim 1, wherein the vacuum container constituting the processing chamber and the vacuum container constituting the measurement chamber have substantially the same structure.   3. The positional relationship between an irradiation object in an irradiation state in the processing chamber and an ion beam and the positional relationship between a beam measuring instrument and the ion beam in the measurement chamber are substantially the same. The ion irradiation apparatus of description.   An electromagnet having two pairs of magnetic poles is used, and one of the pair of magnetic poles constitutes the first beam collimator, and the other pair of magnetic poles constitutes the second beam collimator. The ion irradiation apparatus according to claim 1.   The ion irradiation apparatus according to claim 1, wherein the beam measuring instrument measures at least one of a beam current, a cross-sectional dimension, a position, and a scanning width of the ion beam.   The ion irradiation apparatus according to claim 1, further comprising a controller that controls an ion beam incident on the processing chamber using measurement information from the beam measuring instrument.   The ion irradiation apparatus according to claim 1, further comprising an accelerator / decelerator for accelerating or decelerating the ion beam between the ion source and the beam scanner.

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