JP2008235044A - Beam profile monitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a beam profile monitor in which performance is recovered easily and in a short time without using a heavy machine such as a crane, and in which there is less possibility of moisture invading into a vacuum chamber. <P>SOLUTION: This is the beam profile monitor 10 which has an irradiation face 10a opposing to an ion beam source and measures intensity distribution of an ion beam in an irradiation face. This is equipped with a frame body 12 to surround the irradiation face without shielding the ion beam, a water-cooled tabular cooling support plate 14 having a plurality of slit holes 14a which are fixed to the frame body and in which the ion beam 3 can pass, and a plurality of Faraday cups 18 which are positioned on a rear face side of the ion beam source of the cooling support plate and which respectively measure the intensity of the ion beam 3 passed through the plurality of the slit holes independently. The Faraday cups 18 are detachably mounted on the frame body from the rear face side of the frame body 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a beam profile monitor for an ion implantation apparatus.

  An ion implantation apparatus is an apparatus that extracts a desired ion species from an ion source that generates ions, accelerates or decelerates the energy to a desired energy, and implants ions into an implantation surface of a substrate.

  In such an ion implantation apparatus, a beam profile monitor is installed to measure the size, shape, and intensity distribution of the ion beam, and the ion beam implantation amount is determined based on the measured value. It has become.

  A beam profile monitor has already been disclosed in Patent Document 1, for example.

  An object of the “ion implantation apparatus” of Patent Document 1 is to provide an ion implantation apparatus that includes a low-cost ion beam distribution measurement apparatus and that has improved ion implantation throughput.

  As shown in FIG. 4, this ion implantation apparatus extracts a desired ion species from an ion source that generates ions, accelerates or decelerates to a desired energy, and scans and implants ions onto the substrate implantation surface by a scanner. In the ion implantation apparatus, the Faraday cup 50, which is arranged on the downstream side of the substrate and measures the current value of the ion beam, is arranged between the substrate and the Faraday cup 50, and moves in the same direction as the scanning direction of the ion beam B. The ion beam distribution measuring apparatus including a shielding plate 54 having a single slit 52 is possible.

JP 2006-114289 A, “Ion implantation apparatus”

  Conventionally, a beam profile monitor as shown in FIG. 5A has been used to irradiate the entire surface of a large substrate (for example, 670 mm × 750 mm) with an ion beam. The beam profile monitor 60 is a box-shaped container 62 having an irradiation surface 61 that covers the large substrate 1, and has an elongated slit 61 a that allows the ion beam 2 to pass through the irradiation surface 61.

  5B is a cross-sectional view taken along the line BB of FIG. 5A, and FIG. 5C is a view taken along the line CC of FIG. 5B and 5C, 63 is a Faraday cup, 64 is a suppression electrode, 65 is an ion suppression electrode, 66 is a cooling support plate, 67a, 67b, 67c and 67d are insulators, and 68 is a fixed support plate. However, the suppression electrode 64 and the fixed support plate 68 may be the same.

The Faraday cup 63 is grounded to the box-shaped container 62 through an ammeter (not shown), and detects the intensity of the ion beam 2 from the current emitted from the ion beam 2 (having a positive charge) that has passed through the slit 61a. .
The suppression electrode 64 is applied negative (−) and suppresses secondary electrons generated in the Faraday cup 63. The ion suppression electrode 65 is applied positively (+) and suppresses the entry of floating ions charged positively (+). The cooling support plate 66 is cooled by flowing cooling water through an internal cooling pipe, and absorbs heat of the beam to prevent overheating of the support plate itself and the inside.
Each of these members has a structure in which the bottom plate of the box-shaped container 62 is sequentially stacked via a fixed support plate 68 and insulators 67a, 67b, 67c, 67d.

  When the above-described ion implantation apparatus is used continuously for a long time, a measurement error occurs in the beam profile monitor that measures the beam shape due to the occurrence of contamination and insulation failure caused by the material gas. For this reason, the monitor body was regularly replaced.

  In other words, since the beam profile monitor is installed in a device that uses gas such as diborane or phosphine, if the device is operated for a long time, the insulation resistance of the insulator decreases, and the electric resistance of the Faraday cup surface increases (insulation) due to direct beam irradiation. ), Etc. occur. As a result, the correct beam current cannot be measured, and periodic replacement is required.

Conventionally, the beam profile monitor has been replaced with the main body when the device is stopped during regular maintenance or the like. However, since the profile monitor for a large substrate is large (for example, 800 mm × 900 mm) and heavy (for example, about 300 kg), a heavy machine such as a crane is required for the replacement work, and there is a problem that manpower and time are required for the replacement work.
In addition, the beam profile monitor is connected to the cooling piping for the cooling support plate 66 and the power supply lines of the suppression electrode 64 and the ion suppression electrode 65. Therefore, it takes time and effort to replace these, and maintenance time is also required. There was a problem that was too long.
Furthermore, when the cooling pipe is removed, moisture remains in the vacuum chamber, which may have adverse effects such as taking time for evacuation after maintenance.

  The present invention has been developed to solve the above-described problems. That is, the object of the present invention is to provide a beam profile monitor that can easily recover performance in a short time without using heavy equipment such as a crane, and that the moisture is less likely to enter the vacuum chamber at that time. There is to do.

According to the present invention, there is provided a beam profile monitor that has an irradiation surface facing an ion beam source and measures the intensity distribution of the ion beam on the irradiation surface,
A frame surrounding the irradiated surface without blocking the ion beam;
A plate-like cooling support plate fixed to the frame body and having a plurality of slit holes through which an ion beam can pass;
A plurality of Faraday cups, which are located on the back side of the cooling support plate with respect to the ion beam source and independently measure the intensity of the ion beam that has passed through the plurality of slit holes,
A beam profile monitor is provided, wherein the Faraday cup is detachably attached to the frame from the back side of the frame.

According to a preferred embodiment of the present invention, the Faraday cup is a conductive metal container extending along the plurality of slit holes and having an open slit hole side.
A cup support member that supports the one or more conductive metal containers via an insulator is further provided, and the cup support member is detachably attached to the frame body from the back side.

In addition, an auxiliary electrode is provided between the cooling support plate and the Faraday cup,
The auxiliary electrode is detachably attached to the cooling support plate from the back side of the frame body from which the Faraday cup is removed.

  The auxiliary electrode is an ion suppression electrode and / or a suppression electrode.

  Furthermore, a heat-resistant protective plate having a slit hole that is the same as or narrower than the cooling support plate and is detachably attached to the irradiation surface of the cooling support plate is provided.

  According to the configuration of the present invention, the Faraday cup is detachably attached to the frame from the back side of the frame surrounding the irradiation surface without blocking the ion beam. By removing only the signal line of the Faraday cup without removing the suppression electrode and the power supply line of the suppression electrode, it is possible to remove and replace only the Faraday cup having a high exchange frequency independently from the back side of the frame.

According to a preferred embodiment of the present invention, the auxiliary electrode (ion suppression electrode and / or suppression electrode) positioned between the cooling support plate and the Faraday cup is also powered from the rear side of the frame body from which the Faraday cup is removed. It can be replaced by removing only the line.
Furthermore, the heat-resistant protective plate attached to the irradiation surface of the cooling support plate can also be easily replaced from the front side.

Therefore, when the ion implanter is used continuously for a long time, all parts that cause measurement errors can be replaced as necessary due to contamination caused by material gas and insulation failure, so it is easy without using heavy equipment such as cranes. In addition, performance can be recovered in a short time.
Moreover, since it is not necessary to remove the cooling pipes when replacing these, the possibility of moisture entering the vacuum chamber can be greatly reduced.
Therefore, the time required for replacement is drastically reduced and the maintenance time can be shortened. Further, since it is not necessary to replace the heavy cooling system, the work itself becomes light work and the replacement work becomes easy.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 is an overall configuration diagram of an ion implantation apparatus including a beam profile monitor according to the present invention. In this figure, (A) is a plan view and (B) is a BB cross-sectional view thereof.
In this figure, 1 is a substrate, 2 is a substrate moving device, 3 is an ion beam, 4 is a beam irradiation window, 5 is a vacuum processing chamber, and 6 is an evacuation pump.

The substrate 1 is, for example, a large glass substrate (for example, 670 mm × 750 mm), and is placed on the substrate moving device 2 so as to lean on it with a certain inclination angle (for example, 10 ° backward inclination). The substrate moving device 2 moves horizontally so as to block the irradiation direction of the ion beam 3 and irradiates the surface of the substrate 1 with the ion beam 3.
The ion beam 3 is irradiated into the vacuum processing chamber 5 from an ion beam source (not shown) through the beam irradiation window 4. The vacuum exhaust pump 6 exhausts gas from the inside of the vacuum processing chamber 5 and depressurizes the inside to a degree of vacuum suitable for ion beam injection.

  Inside the vacuum processing chamber 5, a beam profile monitor 10 of the present invention is attached to the back side of the ion beam source from the position through which the substrate moving device 2 passes, facing the ion beam source. In this example, the upper end portion and the lower end portion of the frame 12 constituting the monitor 10 are fixed to the vacuum processing chamber 5 via fixtures 11a and 11b. Further, an openable / closable monitor door 7 is provided on the back surface of the vacuum processing chamber 5 so that the back side of the monitor 10 can be accessed from the back surface during maintenance. The monitor door 7 is preferably an open / close door having a hinge, but may have a structure in which the entire door can be removed.

  FIG. 2 is a front view of the beam profile monitor 10 according to the present invention, and FIG. 3 is a cross-sectional view taken along the line AA of FIG. In this figure, a beam profile monitor 10 of the present invention is an apparatus which has an irradiation surface 10a facing an ion beam source and measures the intensity distribution of the ion beam 3 on this irradiation surface.

  In FIG. 2, a part above the C-C line is a front view of the monitor 10, a b part between the C-C line and the D-D line is a diagram with a heat-resistant protective plate 13 to be described later removed, D- The part c below the D line is a view in which an ion suppression electrode 16 and a suppression electrode 17 described later are further removed.

  As shown in FIGS. 2 and 3, the beam profile monitor 10 of the present invention includes a frame body 12, a cooling support plate 14, and a Faraday cup 18 in order from the irradiation surface side.

The frame 12 is configured to surround the irradiation surface 10a without blocking the ion beam 3 larger than the irradiation surface 10a. The frame 12 is rectangular in this example, but the present invention is not limited to this, and may have other shapes (for example, circular, trapezoidal, etc.).
The cooling support plate 14 is a flat plate fixed to the irradiation surface side of the frame body 12. Cooling water is passed through a water pipe (not shown) to absorb the heat quantity of the beam, thereby cooling the cooling support plate itself and the overheating inside thereof. It is preventing.
The cooling support plate 14 has a plurality (23 in this figure) of elongated slit holes 14a through which the ion beam 3 can pass. In this example, the slit holes 14a extend over the entire width of the ion beam 3 and are spaced at a constant interval in the height direction, but may also be divided in the width direction.

The Faraday cup 18 is located on the back side of the ion beam source of the cooling support plate 14 and is externally connected via a signal line (not shown) so as to independently measure the intensity of the ion beam 3 that has passed through the plurality of slit holes 14a. Connected to an ammeter.
The connection between the signal line and the Faraday cup 18 is preferably a pin connection that can be easily attached and detached without a tool.

As shown in FIG. 2, the Faraday cup 18 is a conductive metal container that extends along the plurality of slit holes 14 a and is open on the slit hole side.
As shown in FIG. 3, the beam profile monitor 10 of the present invention further includes a plurality of cup support members 20. Each cup support member 20 supports one or more (four in this figure) conductive metal containers via an insulator 19 and is detachably attached to the frame 12 from the back side.

In this example, the attachment / detachment mechanism includes a positioning pin 20a provided at an end of each cup support member 20, a positioning groove 12a provided in the frame 12, and a fixing plate 21 that closes the groove, and the positioning pin 20a Each cup support member 20 is fixed at a predetermined position by fitting with the positioning groove 12a of the frame body 12, and each cup support member 20 is fixed to the frame body 12 with screws, pins or the like. It is fixed to the body 12. The attachment / detachment mechanism is not limited to this example, and may be a known mechanism such as a flange and a bolt.
With the above-described configuration, one or a plurality of (four in this figure) Faraday cups 18 can be easily attached and detached from the back side of the frame body 12 together with the cup support members 20.

  In this example, the auxiliary electrodes 16 and 17 are the ion suppression electrode 16 and the suppression electrode 17 that are insulated from each other via the insulator 15. The ion suppression electrode 16 is applied positive (+) via a power supply line (not shown), and suppresses the entry of floating ions charged positive (+). The suppression electrode 17 is applied negative (−) via a power line (not shown) to suppress secondary electrons generated in the Faraday cup. One or both of the ion suppression electrode 16 and the suppression electrode 17 can be omitted as necessary.

The auxiliary electrodes 16 and 17 are located between the cooling support plate 14 and the Faraday cup 18, and are attached to the cooling support plate 14 so as to be detachable from the back side of the frame 12 from which the Faraday cup 18 is removed.
In this example, the means for attaching the auxiliary electrodes 16 and 17 to the cooling support plate 14 is an insulating bolt 23 that is fixed via an insulator 22. The auxiliary electrodes 16 and 17 are integrated through an insulator 15 and are unitized to a predetermined size, and each unit is preferably fixed to the cooling support plate 14 with an insulating bolt 23. .

  With the above-described configuration, the auxiliary electrodes (ion suppression electrode 16 and suppression electrode 17) positioned between the cooling support plate 14 and the Faraday cup 18 are also connected to the respective power lines from the back side of the frame body 12 from which the Faraday cup 18 is removed. It can be easily replaced by removing only.

Furthermore, the beam profile monitor 10 of the present invention includes a heat-resistant protective plate 13 that is detachably attached to the irradiation surface of the cooling support plate 14 with bolts or the like. The heat-resistant protective plate 13 has a slit hole that is the same as or narrower than the slit hole 14 a of the cooling support plate 14. The heat-resistant protective plate 13 is preferably a thin plate having a thickness of about 1 to 2 mm made of a material having high heat resistance and a low coefficient of thermal expansion (for example, molybdenum).
With this configuration, the heat-resistant protective plate 13 can be easily replaced even when damaged by gas such as diborane or phosphine, or by direct beam irradiation.

As described above, the profile monitor according to the present invention is conventionally manufactured in an integral structure, and is replaced with the main body every time the ion implantation apparatus is maintained. Since these are the ion suppression electrode, the suppression electrode, and the Faraday cup, only these can be replaced independently.
In addition, the ion suppression electrode, the suppression electrode, and the Faraday cup can be removed by unitization, and the replacement work is simplified.

  According to the configuration of the present invention described above, the Faraday cup 18 is detachably attached to the frame body 12 from the back side of the frame body 12 surrounding the irradiation surface 10a without blocking the ion beam 3, so that the cooling support plate Only the Faraday cup 18 having a high replacement frequency is singly separated by removing only the signal line of the Faraday cup 18 without removing the cooling pipe 14 and the power supply lines of the ion suppression electrode 16 and the suppression electrode 17. Can be removed and replaced.

Further, the auxiliary electrode (ion suppression electrode 16 and / or suppression electrode 17) positioned between the cooling support plate 14 and the Faraday cup 18 also removes only the power line from the back side of the frame 12 from which the Faraday cup 18 is removed. Can be exchanged.
Furthermore, the heat-resistant protective plate 13 attached to the irradiation surface of the cooling support plate 14 can also be easily replaced from the front side.

Therefore, when the ion implanter is used continuously for a long time, all parts that cause measurement errors can be replaced as necessary due to contamination caused by material gas and insulation failure, so it is easy without using heavy equipment such as cranes. In addition, performance can be recovered in a short time.
Moreover, since it is not necessary to remove the cooling pipes when replacing these, the possibility of moisture entering the vacuum chamber can be greatly reduced.
Therefore, the time required for replacement is drastically reduced and the maintenance time can be shortened. Further, since it is not necessary to replace the heavy cooling system, the work itself becomes light work and the replacement work becomes easy.

  In addition, this invention is not limited to embodiment mentioned above, Of course, it can change variously in the range which does not deviate from the summary of this invention.

1 is an overall configuration diagram of an ion implantation apparatus including a beam profile monitor according to the present invention. It is a front view of the beam profile monitor by this invention. It is AA sectional drawing of the beam profile monitor of FIG. 10 is a schematic diagram of an “ion implantation apparatus” of Patent Document 1. FIG. It is a block diagram of the conventional beam profile monitor.

Explanation of symbols

1 substrate, 2 substrate moving device, 3 ion beam, 4 beam irradiation window,
5 Vacuum processing chamber, 6 Vacuum pump, 7 Monitor door,
10 Beam profile monitor, 10a Irradiation surface,
11a, 11b fixture, 12 frame, 12a positioning groove,
13 heat-resistant protective plate, 14 cooling support plate, 14a slit hole,
15 insulator, 16 ion suppression electrode (auxiliary electrode),
17 suppression electrode (auxiliary electrode), 18 Faraday cup,
19 insulator, 20 cup support member, 20a positioning pin,
22 insulators, 23 insulation bolts

Claims (5)

A beam profile monitor having an irradiation surface facing an ion beam source and measuring an intensity distribution of the ion beam on the irradiation surface,
A frame surrounding the irradiated surface without blocking the ion beam;
A plate-like cooling support plate fixed to the frame body and having a plurality of slit holes through which an ion beam can pass;
A plurality of Faraday cups, which are located on the back side of the cooling support plate with respect to the ion beam source and independently measure the intensity of the ion beam that has passed through the plurality of slit holes,
The beam profile monitor, wherein the Faraday cup is detachably attached to the frame from the back side of the frame. The Faraday cup is a conductive metal container extending along the plurality of slit holes and having an opening on the slit hole side,
A cup support member that supports one or more of the conductive metal containers via an insulator is further provided, and the cup support member is detachably attached to the frame body from the back side. Item 4. The beam profile monitor according to Item 1. Comprising an auxiliary electrode positioned between the cooling support plate and the Faraday cup;
2. The beam profile monitor according to claim 1, wherein the auxiliary electrode is detachably attached to the cooling support plate from a rear side of the frame body from which the Faraday cup is removed.   The beam profile monitor according to claim 3, wherein the auxiliary electrode is an ion suppression electrode and / or a suppression electrode.   2. The beam profile monitor according to claim 1, further comprising a heat-resistant protective plate having a slit hole that is the same as or narrower than the cooling support plate and is detachably attached to an irradiation surface of the cooling support plate. .

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