JP2008269899A - Ion implanting device and control method of ion implanting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion implanting device and a control method of the ion implanting device, capable of restraining generation of charge-up or particles as much as possible, as well as preventing fall of a production yield or a device working rate. <P>SOLUTION: In setting up an ion beam 3, an ion beam shape with an ion beam width or the like in a desired direction is obtained with the use of a faraday cup 10 or a faraday cup 11. A destruction rate prediction part 21, based on a corresponding relation of an ion beam shape acquired beforehand and a destruction rate of a charge-up evaluation element, predicts a destruction rate of the charge-up evaluation element corresponding to the obtained ion beam shape. When the predicted destruction rate of the charge-up evaluation element exceeds a threshold set beforehand, a judgment part 22 adjusts the ion beam shape to make a destruction rate of the charge-up evaluation element not more than the threshold through a device controller 12 for controlling ion implantation in the above corresponding relation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ion implantation apparatus used in a semiconductor device manufacturing process and the like and a method for controlling the ion implantation apparatus.

  In a semiconductor device manufacturing process, an ion implantation apparatus is used to introduce impurities into a semiconductor wafer. In recent years, ion implantation apparatuses have been required to suppress charge-up and particle generation. This is because charge-up causes dielectric breakdown of the gate insulating film and the like, and adhesion of particles to the wafer causes changes in semiconductor device characteristics and element pattern formation failure due to a decrease in implantation amount. . In a fine semiconductor device, since the element structure is reduced, charge-up and generation of particles in the ion implantation process are factors that greatly reduce the product yield. For this reason, with the miniaturization of design rules, ion implantation apparatuses are required to manage charge-up and particles more strictly.

  In an ion implantation apparatus, charge-up and particle management are performed by periodically performing ion implantation for evaluation and evaluating the result of ion implantation. For example, when evaluating charge-up, a TEG (Test Element Group) called an antenna MOS (Metal Oxide Semiconductor) is formed on a wafer in ion implantation for evaluation. The degree of charge-up due to ion implantation depends on the dielectric breakdown rate of the antenna MOS when a predetermined potential difference is applied between the electrodes of the antenna MOS provided on both sides of the insulating film with the dielectric breakdown voltage of the antenna MOS interposed therebetween. Be evaluated.

  When evaluating particles, ion implantation for evaluation is performed on a wafer (bare wafer) on which no pattern is formed. The number of particles generated in the ion implantation apparatus is evaluated based on the number of particles increased on the wafer (a value obtained by subtracting the number of particles before ion implantation from the number of particles after ion implantation).

  However, such a management method using ion implantation for evaluation cannot grasp the state of the ion implantation apparatus that changes from time to time between the previous evaluation ion implantation and the next evaluation ion implantation. In other words, if maintenance of the ion implanter is performed when the evaluation ion implantation result is out of the management standard, the product ion implantation performed before the evaluation ion implantation out of the management standard is performed by ion implantation. The device may be implemented in a state outside the management standard. For this reason, in order to suppress a decrease in product yield, a large margin is provided in the management standard, or a maintenance cycle of the ion implantation apparatus is empirically shortened. In such a management method, maintenance is performed even when the ion implantation apparatus is in a state where ion implantation of a product can be performed without any problem. That is, the operating rate of the ion implantation apparatus is reduced.

  Various countermeasures have been proposed as countermeasures. For example, Patent Literature 1 and Patent Literature 2 disclose measures for improving charge-up. In Patent Document 1, the ion beam spot is divided into a plurality of areas, the beam current in each area is measured, and the maximum value of the beam current is less than a predetermined value between the arc chamber of the ion source and the extraction electrode. The gap length between them is controlled. As a result, the current density of the ion beam is reduced, and charge-up can be suppressed. Also, in Patent Document 2, in an ion implantation apparatus equipped with an ion beam neutralization device (electron shower) that irradiates electrons to an ion beam, the electron beam current density distribution is set to a predetermined value or less. The amount of electron supply from the shower is controlled. As a result, the evaluation for charge-up can be omitted.

Patent Document 3 discloses an improvement measure for particles. In the ion implantation apparatus of Patent Literature 3, particle monitors are installed not only in an ion implantation unit in which a wafer is accommodated but also in several beam line units such as an ion source unit, a mass analysis unit, and an acceleration / deceleration unit. Thereby, the generation | occurrence | production location of a particle is identified rapidly. Further, when the particle generation location is the beam line portion, the ion beam diameter is reduced to a predetermined beam diameter by increasing the extraction acceleration voltage or the like, thereby reducing the generation of particles.
JP-A-6-101040 JP-A-6-36736 JP 2004-356297 A

  However, only the control of the beam current density as disclosed in Patent Document 1 and Patent Document 2 cannot completely suppress the charge-up, and element breakdown occurs even when these techniques are applied. To do. Therefore, in reality, it is necessary to perform charge-up evaluation by ion implantation for evaluation. Therefore, the above-described reduction in product yield and reduction in device operation have not been solved. In particular, TEG evaluation of an antenna MOS or the like requires a great amount of measurement time, which is a major factor for reducing the apparatus operation rate. In addition, since the TEG characteristics themselves are lot-dependent, the problem that management is complicated has become apparent.

  On the other hand, the technique disclosed in Patent Document 3 employs a technique of reducing the ion beam diameter by increasing the extraction acceleration voltage and decreasing the subsequent acceleration voltage. However, recent ion implantation apparatuses are often used in a state where the extraction acceleration voltage is maximum in order to acquire more ion beam current. In this case, the ion beam diameter cannot be reduced. In addition, when decelerating at a later stage as in a large current ion implantation apparatus, there is a concern about an increase in energy contamination. Further, the most fatal problem is that the particle monitor can detect the generated particles but cannot predict the generation of particles. Therefore, even if the technique of Patent Document 3 is applied, it is impossible to prevent a decrease in product yield.

  In a long-term operation, the ion implantation apparatus expands the slit portion of the extraction electrode, and attaches and deposits the source gas and its reaction product on the periphery of the opening of the aperture (analysis slit). Further, the state of the ion beam also changes due to a mistake in mounting components such as an ion source during maintenance. For this reason, the state of charge-up and particle generation changes from moment to moment.

  The present invention has been proposed in view of the above-described conventional circumstances, and even when operated for a long period of time, it is possible to suppress charge-up and particle generation as much as possible, and to reduce product yield and device operation rate. It is an object of the present invention to provide an ion implantation apparatus and a method for controlling the ion implantation apparatus that can prevent the above.

  In order to achieve the above-described object, the present invention employs the following technical means. First, the present invention presupposes an ion implantation apparatus having a mechanism for causing an ion beam extracted from an ion source and subjected to mass analysis to enter a substrate through an aperture and to supply electrons to the ion beam that has passed through the aperture. . And the ion implantation apparatus which concerns on this invention is provided with a measurement means, a destruction rate prediction part, and a determination part. The measuring means acquires a physical quantity having a correlation with the breakdown rate of the charge-up evaluation element. The destruction rate prediction unit predicts the destruction rate of the charge-up evaluation element corresponding to the physical quantity acquired by the measuring unit based on the correspondence relationship between the physical quantity and the destruction rate acquired in advance. When the predicted breakdown rate of the charge-up evaluation element exceeds a preset threshold value, the determination unit uses the device controller that controls the ion implantation to convert the physical quantity into the corresponding relationship of the charge-up evaluation element. The destruction rate is adjusted to be equal to or less than the above threshold value.

  In the above configuration, the measurement unit acquires, for example, the ion beam shape after passing through the aperture as the physical quantity. Here, the ion beam shape refers to a shape parameter such as a width in a predetermined direction in the cross-sectional shape of the ion beam and a radius of the ion beam. In this configuration, when the predicted breakdown rate of the charge-up evaluation element exceeds a preset threshold value, it is possible to employ a configuration in which the ion beam shape is adjusted by suppressing ion beam diffusion. Further, as a physical quantity, a difference between the ion beam shape immediately before passing through the aperture and the ion beam shape after passing through the aperture may be acquired. Further, in the configuration in which the aperture is movably disposed between the position inserted in the ion beam trajectory and the position outside the trajectory, the measurement means can measure ions when the aperture is in the position outside the trajectory as a physical quantity. The difference between the beam shape and the ion beam shape when the aperture is inserted into the trajectory can also be obtained.

  The measuring means may acquire a current flowing between the substrate and the ground potential during ion implantation as a physical quantity. In this configuration, when the predicted breakdown rate of the charge-up evaluation element exceeds a preset threshold, it is possible to employ a configuration in which the current is adjusted by increasing the amount of electrons supplied to the ion beam. .

  In the above configuration, it is preferable to obtain an integrated time during which the ion beam irradiates the periphery of the aperture of the aperture and to stop the ion implantation process when the integrated time exceeds a preset threshold value. Alternatively, it is preferable that the integrated time when the ion beam irradiates the periphery of the aperture of the aperture is acquired and a warning is issued when the integrated time is equal to or less than a preset threshold value and a positive value. .

  The integration time can be calculated, for example, from the ion beam shape after passing through the aperture and the ion beam irradiation time. The integration time can also be calculated from the difference between the ion beam shape immediately before passing the aperture and the ion beam shape after passing the aperture, and the ion beam irradiation time. Furthermore, in the configuration in which the aperture is movably disposed between the position inserted in the trajectory of the ion beam and the position outside the trajectory, the integration time is the shape of the ion beam when the aperture is in the position outside the trajectory. And the difference from the ion beam shape when the aperture is located at the position inserted in the trajectory, and the ion beam irradiation time.

  On the other hand, in another aspect, the present invention provides an ion implantation having a mechanism for causing an ion beam extracted from an ion source and subjected to mass analysis to enter a substrate through the aperture and to supply electrons to the ion beam that has passed through the aperture. An apparatus control method can also be provided. In other words, the ion implantation apparatus control method according to the present invention first acquires a physical quantity having a correlation with the breakdown rate of the charge-up evaluation element. Next, the destruction rate of the charge-up evaluation element corresponding to the acquired physical quantity is predicted based on the correspondence relationship between the physical quantity and the destruction rate acquired in advance. When the predicted breakdown rate of the charge-up evaluation element exceeds a preset threshold value, the physical quantity is adjusted to a state in which the breakdown rate of the charge-up evaluation element is equal to or less than the threshold value in the correspondence relationship.

  The physical quantity is, for example, an ion beam shape after passing through the aperture. In this case, when the predicted breakdown rate of the charge-up evaluation element exceeds a preset threshold value, it is possible to adopt a configuration in which the ion beam shape is adjusted by suppressing ion beam diffusion. The physical quantity may be a difference between an ion beam shape immediately before passing through the aperture and an ion beam shape after passing through the aperture. Further, when the aperture is movable between the position inserted in the trajectory of the ion beam and the position outside the trajectory, the physical quantity is the shape of the ion beam when the aperture is in the position outside the trajectory, and the aperture is It may be a difference from the shape of the ion beam at the position inserted in the orbit.

  The physical quantity may be a current that flows between the substrate and the ground potential during ion implantation. In this case, when the predicted breakdown rate of the charge-up evaluation element exceeds a preset threshold value, it is possible to employ a configuration in which the current is adjusted by increasing the amount of electrons supplied to the ion beam. .

  In the ion implantation apparatus control method described above, the ion implantation process is stopped when the ion beam acquires the accumulated time during which the aperture periphery of the aperture is irradiated and the accumulated time exceeds a preset threshold value. It is preferable to do. Alternatively, it is preferable to acquire an integrated time when the ion beam irradiates the periphery of the aperture of the aperture, and to issue a warning when the integrated time is equal to or less than a preset threshold value and a positive value.

  The integration time can be calculated, for example, from the ion beam shape after passing through the aperture and the ion beam irradiation time. The integration time can also be calculated from the difference between the ion beam shape immediately before passing the aperture and the ion beam shape after passing the aperture, and the ion beam irradiation time. Furthermore, when the aperture is movable between the position inserted in the trajectory of the ion beam and the position outside the trajectory, the integration time is determined by the shape of the ion beam when the aperture is at the position outside the trajectory, and It can be calculated from the difference from the ion beam shape when the aperture is at the position inserted in the trajectory and the ion beam irradiation time.

  ADVANTAGE OF THE INVENTION According to this invention, when implementing ion implantation in an ion implantation apparatus, it can be determined in real time whether charge up generate | occur | produces and also whether a particle generate | occur | produces. In addition, the ion implantation apparatus can be operated for as long as possible in a state where charge-up and particle generation are suppressed within a certain range. As a result, a decrease in product yield can be suppressed, and the apparatus operating rate can be significantly improved.

  In particular, by adopting a configuration that makes a determination based on the difference in ion beam shape before and after the aperture, or the difference in ion beam shape with and without the aperture, whether or not charge-up occurs, It can be determined very accurately whether or not it occurs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram showing an ion implantation apparatus according to a first embodiment of the present invention. As shown in FIG. 1, the ion implantation apparatus 100 includes an ion source 1, an extraction electrode (extraction acceleration unit) 2, and a mass analysis unit 4. The ions generated by the ion source 1 are extracted by the potential applied to the extraction electrode 2 and then mass-analyzed in the process of passing through the mass analyzer 4 to become an ion beam 3 made of desired ions. In the present embodiment, the extraction electrode 2 is configured to be movable, and the distance between the ion source 1 and the extraction electrode 2 can be changed.

  An aperture (analysis slit) 5 is arranged on the output side of the mass analyzer 4. The aperture 5 has an opening on the passage path of desired ions, and has a function of removing excess ions and particles from the ion beam 3. A wafer holder 8 is disposed in the path of the ion beam 3 that has passed through the aperture 5. A semiconductor wafer 7 (hereinafter referred to as a wafer 7) to be ion-implanted is placed on the wafer holder 8, and ions are uniformly implanted onto the wafer by mechanically scanning the wafer holder 8. Further, an electron shower 6 for supplying electrons with low energy to the ion beam 3 is provided between the aperture 5 and the wafer holder 8 in order to neutralize the ion beam 3.

  Further, the ion implantation apparatus of the present embodiment is inserted into the orbit of the ion beam 3 from a position outside the orbit of the ion beam 3 when the ion beam is adjusted (hereinafter referred to as setup) before the ion implantation process. A Faraday cup 10 for measuring the beam current and ion beam shape of the ion beam 3 is provided. Further, a Faraday cup 11 for measuring the beam current and ion beam shape of the ion beam 3 during ion implantation is provided on the downstream side of the wafer holder 8 in the traveling direction of the ion beam 3.

  A series of operations of each part of the ion implantation apparatus 100 accompanying the ion implantation is controlled by the apparatus controller 12. Data acquired by the Faraday cup 10 and the Faraday cup 11 is stored in a storage unit such as an HDD (Hard Disk Drive) provided in the device controller 12.

  In the ion implantation apparatus 100 having the above-described configuration, the ion beam 3 extracted from the ion source 1 by the extraction electrode 2 during the ion implantation is supplied from the electron shower 6 after passing through the mass analysis unit 4 and the aperture 5. Neutralized by electrons and injected into the wafer 7. The amount of electrons supplied from the electron shower 6 to the ion beam 3 is set for each ion implantation condition such as implanted ion species, implantation energy, and beam current. Note that the amount of electron supply is determined by experiment using, for example, a known charge-up evaluation element such as an antenna MOS so that the evaluation element is not destroyed due to charge-up.

  When the ion implantation process is continuously performed by the ion implantation apparatus 100, the ion beam 3 extracted from the ion source 1 sputters the slit portion of the extraction electrode 2 made of carbon or the like, so that the slit portion gradually expands.

  FIG. 2 is a schematic diagram showing the ion implantation apparatus in a state in which the slit portion of the extraction electrode 2 is enlarged. In FIG. 2, the control system is not shown. When the slit portion of the extraction electrode 2 expands, the diameter of the ion beam extracted from the ion source 1 by the extraction electrode 2 increases. For this reason, the area of the ion beam 3 that irradiates the periphery of the opening of the aperture 5 after passing through the mass analyzer 4 increases. The ion beam 3 having a positive charge travels in the ion implantation apparatus 100 in a state where electrons are attracted to the periphery by the positive charge (potential). However, in the case of the ion beam 3 extracted to the extraction electrode 2 whose slit portion is enlarged, as shown in FIG. 2, when the ion beam 3 passes through the aperture 5, electrons associated with the ion beam 3 are not in the aperture 5. It is peeled off by the end of the opening 5a. Therefore, when the slit portion of the extraction electrode 2 is enlarged, the amount of electrons accompanying the ion beam 3 that has passed through the aperture 5 decreases, and the potential increases relatively in the positive direction. For this reason, the neutralization of the ion beam 3 becomes insufficient with the electron supply amount from the electron shower 6 set in advance, and the wafer 7 is charged up.

  Accordingly, in the present embodiment, the shape of the ion beam 3 that has passed through the aperture 5 is acquired as a physical quantity having a correlation with the breakdown rate of the charge-up evaluation element, and the charge-up of the wafer 7 is performed based on the shape of the ion beam 3. The structure which detects the degree of is adopted.

  FIG. 3 shows the width of the ion beam 3 measured in the Faraday cup 11 in the X direction (vertical direction on the paper surface in FIG. 1) and the specific shape formed on the wafer 7 by performing ion implantation with the ion beam 3. It is a figure which shows the relationship with the destruction rate of the MOS capacitor of antenna MOS (charge-up evaluation element) which has the antenna ratio of. In FIG. 3, the horizontal axis corresponds to the X-direction width of the ion beam, and the vertical axis corresponds to the destruction rate of the antenna MOS. FIG. 3 shows data (lots A to F) acquired for a plurality of ion implantation conditions with the same or different ion implantation conditions.

  From FIG. 3, it can be understood that the antenna MOS breakdown rate increases as the X-direction width of the ion beam 3 increases. This indicates that the degree of charge-up of the wafer 7 increases as the width of the ion beam 3 in the X direction increases. Further, it can be understood from FIG. 3 that the ion beam X direction width and the antenna MOS breakdown rate have a substantially linear relationship for each ion implantation condition (for each lot). FIG. 3 illustrates a primary regression line for lot C and a primary regression line for lot E. Note that the X-direction width of the ion beam 3 shows the same relationship even if it is acquired using the Faraday cup 10. In this case, the numerical value on the horizontal axis in FIG. 3 is merely replaced with the X direction width of the ion beam 3 in the Faraday cup 10.

  Therefore, as shown in FIG. 3, the correspondence between the X-direction width of the ion beam 3 and the antenna MOS breakdown rate is acquired in advance, and the slit of the extraction electrode 2 is enlarged using the correspondence. It is possible to grasp in real time the degree of charge-up of the wafer 7 caused by the above.

  Hereinafter, the charge-up detection process performed by the ion implantation apparatus 100 will be described. FIG. 4 is a flowchart showing the procedure of the charge-up detection process. This process is executed by the destruction rate prediction unit 21 and the determination unit 22 (see FIG. 1) included in the ion implantation apparatus 100. The destruction rate prediction unit 21 and the determination unit 22 are stored in, for example, a dedicated circuit, hardware including a processor and a memory such as a RAM (Random Access Memory) and a ROM (Read Only Memory), and the memory. It can be realized by software operating on the above. The linear regression equation showing the correspondence relationship between the X-direction width of the ion beam 3 and the antenna MOS breakdown rate illustrated in FIG. 3 is stored in the breakdown rate prediction unit 21 for each ion implantation condition (for each lot). Yes.

  First, the ion implantation apparatus 100 sets up the ion beam 3 (step S401). At this time, the X direction width of the ion beam 3 is measured by the Faraday cup 11 (or the Faraday cup 10) (step S402). Next, the destruction rate prediction unit 21 reads out the X-direction width of the ion beam 3 acquired by the Faraday cup 11 from the storage unit of the apparatus controller 12, and the X-direction width of the ion beam 3 and the destruction rate of the charge-up evaluation element. The predicted value Y of the antenna MOS destruction rate corresponding to the measured width in the X direction of the ion beam 3 is calculated by a linear regression equation indicating the correspondence relationship with (step S403). At this time, it goes without saying that the destruction rate prediction unit 21 uses a linear regression equation corresponding to the set-up ion implantation conditions and lots to calculate the predicted value Y.

  The calculated predicted value Y is input to the determination unit 22. The determination unit 22 compares the input predicted value Y with the preset upper limit management standard Yc (threshold value) of the antenna MOS breakdown rate. Then, when the predicted value Y is larger than the upper limit management standard Yc, it is determined that the charge-up is abnormal, and when the predicted value Y is equal to or lower than the upper limit management standard Yc, it is determined as normal (step S404). When the determination result is normal, the determination unit 22 causes the apparatus controller 12 to start the ion implantation process (steps S404 No and S405). If the determination result is a charge-up abnormality, the apparatus controller 12 is instructed to reduce the ion beam width. The apparatus controller 12 that has received the instruction first checks whether or not the distance between the ion source 1 and the extraction electrode 2 is the adjustment limit (maximum distance) of the ion implantation apparatus 100 (steps S404 Yes, S406). ). If the distance between the ion source 1 and the extraction electrode 2 does not reach the adjustment limit and can be adjusted, the distance between the ion source 1 and the extraction electrode 2 is increased by a predetermined amount, and the ion beam is increased. 3 diffusion is suppressed. That is, by narrowing the ion beam 3, the width of the ion beam 3 in the X direction is reduced (steps S406 Yes, S407).

  The apparatus controller 12 that has decreased the width of the ion beam 3 sets up the ion beam 3 again in this state (step S401). Then, the X direction width of the ion beam 3 is measured by the Faraday cup 11, and the destruction rate prediction unit 21 calculates the predicted value Y again (steps S402 and S403). The determination unit 22 compares the newly calculated predicted value Y with the upper limit management standard Yc of the antenna MOS breakdown rate (step S404). By repeating this process, the X direction width of the ion beam 3 is adjusted to a state where the predicted value Y is equal to or less than the upper limit management standard Yc. As a result of adjustment, when the predicted value Y is equal to or lower than the upper limit management standard Yc, the determination unit 22 causes the apparatus controller 12 to start the ion implantation process (steps S404 No, S405).

  On the other hand, when the distance between the ion source 1 and the extraction electrode 2 reaches the adjustment limit of the ion implantation apparatus 100 in the process of reducing the width of the ion beam 3 in the X direction, The production is stopped, and the maintenance execution request is notified to the worker through the notification unit 13 (No in steps S406 and S408). Here, the notification means 13 can notify the operator of the maintenance execution request by any method such as light, sound, warning display and the like. If the ion implantation apparatus is an ion implantation apparatus having an electrostatic lens between the aperture 5 and the wafer holding unit 8, the shape of the ion beam 3 may be formed by controlling the electrostatic lens. .

  As described above, according to the present embodiment, it is possible to grasp the degree of charge-up of the wafer 7 immediately before the start of the ion implantation process. For this reason, generation | occurrence | production of charge up can be suppressed and the fall of a product yield can be suppressed. Further, in the ion implantation apparatus of this embodiment, the degree of charge-up of the wafer 7 can be grasped in real time without performing TEG evaluation or the like, and maintenance is performed only when the product cannot be normally produced. Is implemented. For this reason, the apparatus operating rate can be remarkably improved as compared with the prior art.

  In the above description, the correspondence relationship between the X-direction width of the ion beam and the antenna MOS breakdown rate is shown by a linear regression equation, but the correspondence relationship is shown using another regression equation such as an exponential function or a quadratic function. May be. In the above description, the X direction width is used as the ion beam shape. However, any shape parameter indicating the ion beam shape such as the width in a predetermined direction such as the Y direction width or the ion beam radius can be used. Further, in the above description, the antenna MOS is used as the charge-up evaluation element. However, as long as the element has a structure capable of evaluating the charge-up degree of the wafer 7, a charge-up evaluation element having an arbitrary structure may be used. it can.

(Second Embodiment)
In the first embodiment, the configuration for grasping the degree of charge-up in real time based on the ion beam shape has been described. However, the degree of charge-up can be grasped in real time by using another physical quantity.

  FIG. 5 is a schematic configuration diagram showing an ion implantation apparatus 200 of the present embodiment. As shown in FIG. 5, in the ion implantation apparatus 200, a disk current measurement unit 9 that measures a disk current flowing from the mounted wafer 7 to the ground (ground potential) during ion implantation is connected to the wafer holding unit 8. ing. Since other configurations are the same as those of the ion implantation apparatus 100 of the first embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted here. The data acquired by the disk current measuring unit 9 is stored in a storage unit provided in the device controller 12.

  As in the first embodiment, when the ion implantation process is continuously performed by the ion implantation apparatus 200, the slit portion of the extraction electrode 2 gradually expands, and the wafer 7 is charged.

  Therefore, in the present embodiment, a configuration is adopted in which the disk current is acquired as a physical quantity having a correlation with the breakdown rate of the charge-up evaluation element, and the degree of charge-up is detected based on the disk current. The disk current is a current mainly caused by electrons that have reached the wafer 7 accompanying the ion beam 3 flowing to the ground (ground potential) through the wafer holder 8. Therefore, if electrons sufficient to neutralize the ion beam 3 are supplied from the electron shower 6, the electrons flow to the ground when the ion beam 3 reaches the wafer 7, so that a negative disk current (wafer holding) The direction from the portion 8 to the ground is the positive direction). On the other hand, when the ion beam 3, which is insufficiently neutralized with electrons supplied from the electron shower 6, reaches the wafer 7 due to the enlargement of the slit portion of the extraction electrode 2, the amount of electrons flowing to the ground decreases. As a result, the disk current increases (the absolute value decreases).

  FIG. 6 shows a disk current measured by the disk current measuring unit 9 and an antenna MOS (charge-up evaluation element) formed on the wafer 7 by performing ion implantation with the ion beam 3 and having a specific antenna ratio. It is a figure which shows the relationship with the destruction rate of a MOS capacitor. In FIG. 6, the horizontal axis corresponds to the disk current, and the vertical axis corresponds to the destruction rate of the antenna MOS. FIG. 6 shows data (lots A to F) acquired for a plurality of ion implantation conditions with the same or different ion implantation conditions.

  From FIG. 6, it can be understood that the antenna MOS breakdown rate increases as the disk current increases (the absolute value decreases). This indicates that the charge-up of the wafer 7 is progressing as the disk current increases (absolute value decreases). Further, it can be understood that the disk current and the antenna MOS breakdown rate have a corresponding relationship for each ion implantation condition. The correspondence relationship can be expressed by, for example, a regression equation using a function f (x) such as an exponential function or a quadratic function. FIG. 6 illustrates a secondary regression line for lot C and a secondary regression line for lot E.

  Therefore, by acquiring the correspondence between the disk current and the antenna MOS breakdown rate in advance as shown in FIG. 6, the charge-up caused by the expansion of the slit portion of the extraction electrode 2 can be performed using the correspondence. It is possible to grasp the degree of the above in real time.

  Hereinafter, the charge-up detection process performed by the ion implantation apparatus 200 will be described. FIG. 7 is a flowchart showing the procedure of the charge-up detection process. This process is executed by the destruction rate prediction unit 31 and the determination unit 32 (see FIG. 5) included in the ion implantation apparatus 200. The destruction rate predicting unit 31 and the determining unit 32 are realized by, for example, a dedicated circuit, hardware including a processor and a memory such as a RAM or a ROM, and software stored in the memory and operating on the processor. be able to. Note that the regression equation showing the correspondence between the disk current and the antenna MOS breakdown rate illustrated in FIG. 6 is stored in the breakdown rate prediction unit 31 for each ion implantation condition (for each lot).

  First, the ion implantation apparatus 200 sets up the ion beam 3 and starts ion implantation into the wafer 7 (steps S701 and S702). At this time, the disk current measured by the disk current measuring unit 9 is stored in the storage unit in the device controller 12 (step S703). Next, the destruction rate prediction unit 31 reads out the disk current acquired by the disk current measurement unit 9 from the storage unit of the device controller 12, and a regression equation indicating the correspondence between the disk current and the destruction rate of the charge-up evaluation element. Thus, the predicted value Y of the antenna MOS breakdown rate corresponding to the measured disk current is calculated (step S704). At this time, of course, the destruction rate predicting unit 31 uses the set-up ion implantation conditions and the regression equation corresponding to the lot to calculate the predicted value Y.

  The calculated predicted value Y is input to the determination unit 32. The determination unit 32 compares the input predicted value Y with a preset upper limit management standard Yc (threshold value) of the antenna MOS breakdown rate. Then, when the predicted value Y is larger than the upper limit management standard Yc, it is determined that the charge-up is abnormal, and when the predicted value Y is equal to or lower than the upper limit management standard Yc, it is determined as normal (step S705). When the determination result is normal, the determination unit 32 causes the apparatus controller 12 to continue the ion implantation process in the state as it is (steps S705 No, S706). If the determination result is a charge-up abnormality, the determination unit 32 instructs the device controller 12 to increase the amount of electrons supplied to the electron shower 6. The device controller 12 that has received the instruction first checks whether or not the electron supply amount of the electron shower 6 is the adjustment limit (maximum supply amount) (Yes in steps S705 and S707). If the electron supply amount of the electron shower 6 can be increased, for example, the electron supply amount is increased by controlling the filament current of the electron shower 6 and the disk current is decreased (No in steps S707 and S708).

  The apparatus controller 12 having increased the electron supply amount of the electron shower 6 again measures the disk current in this state, and the destruction rate prediction unit 31 calculates the prediction value Y again (steps S703 and S704). The determination unit 32 compares the newly calculated predicted value Y with the upper limit management standard Yc of the antenna MOS breakdown rate (step S705). By repeating this process, the disk current is adjusted to a state where the predicted value Y is equal to or lower than the upper limit management standard Yc. In this process, when the electron supply amount of the electron shower 6 reaches the adjustment limit of the ion implantation apparatus 200, the determination unit 32 stops the production in the ion implantation apparatus 200, and notifies the same as in the first embodiment. The maintenance execution request is notified to the worker through 13 (Yes in steps S707 and S709).

  On the other hand, when the predicted value Y becomes equal to or lower than the upper limit management standard Yc as a result of the adjustment, the determination unit 32 causes the device controller 12 to continue the ion implantation process as it is (steps S705 No, S706).

  As described above, according to the present embodiment, the degree of charge-up can be grasped in real time in the ion implantation apparatus. For this reason, generation | occurrence | production of charge up can be suppressed and the fall of a product yield can be suppressed. In addition, since maintenance is performed only when the product cannot be normally produced, the apparatus operating rate can be significantly improved as compared with the conventional case.

  In the above description, the apparatus controller 12 is configured to increase the electron supply amount of the electron shower 6 based on the instruction of the determination unit 32. However, as in the first embodiment, the ion source 1 and the extraction electrode 2 are used. For example, the width of the ion beam 3 may be decreased by increasing the distance between the two. Even with this configuration, the disk current can be reduced. Furthermore, as in the first embodiment, any charge-up evaluation element having any structure can be used as long as the element has a structure capable of evaluating the degree of charge-up of the wafer 7.

(Third embodiment)
By the way, as explained in the first and second embodiments, when the slit portion of the extraction electrode 2 is enlarged, the area of the ion beam 3 that irradiates the aperture 5 after passing through the mass analyzer 4 increases (see FIG. 2). . At this time, at the periphery of the opening of the aperture 5 irradiated with the ion beam 3, dirt (source gas or a reaction product thereof, hereinafter referred to as deposit) is attached or deposited. When the ion beam 3 is irradiated to the portion where the deposit is deposited, the deposited deposit serves as a dust generation source and generates particles in the ion implantation apparatus. The particles generated in this way are attracted to the potential of the ion beam 3, reach the wafer 7 together with the ion beam 3, and greatly reduce the product yield.

  In the first and second embodiments, even when the slit portion of the extraction electrode 2 is in an enlarged state, the ion implantation apparatus is used as long as normal production is possible while suppressing the occurrence of charge-up. For this reason, it is desirable to suppress generation | occurrence | production of the above-mentioned particle as much as possible. Therefore, in the present embodiment, a configuration that can suppress the generation of the particles as much as possible will be described.

  FIG. 8 is a schematic configuration diagram showing the ion implantation apparatus of the present embodiment. As shown in FIG. 8, the ion implantation apparatus 300 of this embodiment includes a particle monitoring unit 41 in addition to the configuration of the ion implantation apparatus 100 described in the first embodiment. Other configurations are the same as those of the ion implantation apparatus 100 of the first embodiment.

  As described in the first embodiment, the Faraday cup 10 is used for measuring the shape of the ion beam 3 and the ion beam current during setup. The Faraday cup 11 is used for measuring the shape of the ion ion beam 3 and the ion beam current during ion implantation. Further, under the situation where the slit portion of the extraction electrode 2 is not enlarged (the width of the ion beam 3 is not enlarged), the ion beam 3 passes through the opening of the aperture 5. Therefore, the periphery of the opening of the aperture 5 is irradiated to the ion beam 3 when the width of the ion beam 3 exceeds a specific threshold value Wc. Therefore, the time during which the ion beam 3 is measured by the Faraday cups 10 and 11 in a state where the width of the ion beam 3 exceeds the threshold value Wc is the beam irradiation integration time in the aperture 5. The threshold value Wc can be obtained in advance by experiments or the like.

  FIG. 9 shows the relationship between the beam irradiation integration time and the number of increased particles on the wafer 7. In FIG. 9, the horizontal axis corresponds to the beam irradiation integration time, and the vertical axis corresponds to the number of increased particles. From FIG. 9, it can be understood that when the beam irradiation integration time exceeds a certain threshold time Tc (Tc = 5 hours in FIG. 9), the number of increased particles increases. Therefore, in the example of FIG. 9, if the beam irradiation integration time is within the threshold time Tc, the ion implantation process can be performed in a state where the generation of particles is suppressed. FIG. 9 shows data obtained under specific ion implantation conditions (implanted ion species, implantation energy, beam current). The generation of particles strongly depends on ion implantation conditions, that is, ion species, energy, and beam current, as well as ion beam shape (expansion). In the case where the ion beam is relatively difficult to expand, even if the slit portion of the extraction electrode 2 is expanded, the ion beam may not be irradiated to the periphery of the opening of the aperture 5. It is not necessary to provide it. Therefore, when there are a plurality of ion implantation conditions, the ion implantation conditions are set for the threshold time Tc that needs to be set. As a method of providing the threshold time Tc, it may be provided for each ion implantation condition, or the threshold time Tc may be provided for a series of implantation condition groups (recipe groups) including a plurality of ion implantation conditions. In any case, the threshold time Tc can be determined by acquiring the correspondence illustrated in FIG. 9 in advance.

  FIG. 10 is a flowchart showing the particle suppression procedure of this embodiment. This process is mainly executed by the particle monitoring unit 41. The particle monitoring unit 41 can be realized by, for example, a dedicated circuit, hardware including a processor and a memory such as a RAM and a ROM, and software stored in the memory and operating on the processor. . The particle monitoring unit 41 stores a threshold value Wc and a threshold time Tc obtained in advance by an experiment for each ion implantation condition.

  In the ion implantation apparatus 300, when a product is ion-implanted under a specific implantation condition (or implantation condition group), the apparatus controller 12 first checks the apparatus state S stored in the storage unit (step S1001). Here, the device state S refers to a state in which the ion implantation apparatus 100 is in a maintenance standby state (S = 2) and a state in which the aperture 5 is irradiated to the ion beam 3 during ion implantation (S = 1, hereinafter referred to as a maintenance warning state). ) Or a normal state (S = 0).

  As a result of confirming the apparatus state S, if the apparatus is not in the maintenance standby state (S = 2), the apparatus controller 12 performs setup of the ion beam 3 under the designated ion implantation conditions (No in steps S1001 and S1002). At this time, the width W (for example, the width in the X direction) of the ion beam 3 is measured by the Faraday cup 10 (step 1003). Here, it is assumed that the device state S is a normal state (S = 0).

  Next, the particle monitoring unit 41 reads the measured ion beam width W from the storage unit of the apparatus controller 12, and compares the ion beam width W with the above-described threshold value Wc (step S1004). As a result of the comparison, if the ion beam width W is equal to or smaller than the threshold value Wc, the apparatus controller 12 is instructed to start the ion implantation process without changing the apparatus state S from S = 0 (steps S1004 No, S1005, S1006). The apparatus controller 12 starts the ion implantation process after performing the charge-up detection process described in the first embodiment.

  On the other hand, if the ion beam width W exceeds the threshold value Wc as a result of the comparison between the ion beam width W and the threshold value Wc, the particle monitoring unit 41 determines that the ion beam width adjustment count is a preset upper limit count. If the maximum number of times has not been reached, the apparatus controller 12 is instructed to decrease the ion beam width W (No in steps S1004 and S1007). The device controller 12 that has received the instruction reduces the ion beam width by the method described in the first embodiment, for example (step S1008).

  The apparatus controller 12 that has decreased the ion beam width W sets up the ion beam 3 again in this state (step S1002). Then, the Faraday cup 10 measures the ion beam width W, and the particle monitoring unit 41 compares the ion beam width W with the threshold value Wc again (steps S1003 and S1004). When the ion beam width W can be adjusted to be equal to or smaller than the threshold value Wc within the above upper limit number by repeating such adjustment of the ion beam width W, the particle monitoring unit 41 changes the apparatus state S from S = 0. Then, the apparatus controller 12 is instructed to start the ion implantation process (No in steps S1004, S1005, and S1006).

  On the other hand, when the ion beam width W cannot be adjusted to the threshold Wc or less within the upper limit number of times, the particle monitoring unit 41 sets the device state S of the device controller 12 to the maintenance warning state (S = 1) (step S1007 Yes, S1009). Further, the particle monitoring unit 41 starts accumulating the beam irradiation integration time T (step S1010). Then, while the beam irradiation integration time T is equal to or less than the threshold time Tc set in advance as described above, the particle monitoring unit 41 instructs the apparatus controller 12 to start the ion implantation process (No in step S1011). S1006). At this time, the particle monitoring unit 41 notifies the operator that the ion implantation apparatus 300 is in the maintenance warning state (S = 1) through the notification unit 13. Thereby, the operator can grasp that the ion implantation apparatus 300 will be in a maintenance standby state soon.

  After that, by continuing the product processing, when the beam irradiation integrated time T exceeds the threshold time Tc, the particle monitoring unit 41 changes the device state S of the device controller 12 to the maintenance standby state (S = 2) ( Step S1011 Yes, S1012). Then, the particle monitoring unit 41 instructs the apparatus controller 12 to start the ion implantation process in a state where the beam current is temporarily reduced (step S1013). By performing ion implantation in a state where the beam current of the ion beam 3 is reduced in this way, the time required to reach the specified dose increases, but the generation of particles due to the above-described causes is suppressed. be able to.

  As described above, when the apparatus state S becomes the maintenance standby state (S = 2), the apparatus controller 12 prohibits the subsequent execution of the ion implantation process under the ion implantation conditions and includes the ion implantation process. This is notified to the production management device 51 that manages the production of the process. The production management device 51 that has received the notification, is the implantation condition (implantation condition group) to be prohibited to the ion implantation apparatus 300, that is, the implantation condition (implantation condition group) in which the ion beam width W could not be adjusted to the threshold value Wc or less. The introduction of the wafer 7 that requires the ion implantation process is prohibited, and the wafer 7 is introduced into another ion implantation apparatus. At this time, the particle monitoring unit 41 notifies the operator through the notification means 13 that the ion implantation apparatus 300 is in the maintenance standby state (S = 2).

  The maintenance standby state (S = 2) or the maintenance warning state (S = 1) is not changed until the maintenance is executed.

  As described above, according to this embodiment, in the first and second embodiments, the generation of particles can be suppressed as much as possible, and the apparatus can be operated for as long as possible. As a result, it is possible to avoid a decrease in product yield and improve the apparatus operating rate.

  In this embodiment, the example applied to the ion implantation apparatus of the first embodiment has been described. However, the same effect can be obtained also when applied to the ion implantation apparatus described in the second embodiment. it can.

(Fourth embodiment)
In the first and third embodiments described above, the shape of the ion beam 3 is measured by the Faraday cup 10 when the ion beam 3 is set up. Therefore, the ion beam shape is measured at a position after passing through the aperture 5. In order to more accurately grasp the degree of irradiation of the electrons around the ion beam 3 due to the expansion of the shape of the ion beam 3 and the irradiation of the periphery of the opening of the aperture 5, the mass analyzer 4 It is desirable to measure the ion beam shape between the aperture 5 and the aperture 5. Therefore, in the present embodiment, a configuration for measuring the ion beam shape between the mass analyzer 4 and the aperture 5 will be described.

  FIG. 11 is a schematic configuration diagram showing the ion implantation apparatus of the present embodiment. As shown in FIGS. 11 (a) and 11 (b), the ion implantation apparatus 400 is located between the mass analyzer 4 and the aperture 5 (immediately before the aperture 5) from a position outside the orbit of the ion beam 3. A Faraday cup 16 that is inserted into the trajectory of the ion beam 3 and measures the beam current and the ion beam shape of the ion beam 3 is provided. Other configurations are the same as those of the ion implantation apparatus 100 described in the first embodiment. In FIG. 11, the control system is not shown.

  As shown in FIG. 11A, the ion implantation apparatus 400 inserts the Faraday cup 16 and the Faraday cup 10 into the trajectory of the ion beam 3 at the time of setup. Then, the ion beam width W1 (for example, the width in the X direction) immediately before passing through the aperture 5 is measured by the Faraday cup 16. Thereafter, the Faraday cup 16 is moved to a position outside the orbit of the ion beam 3, and the Faraday cup 10 measures the ion beam width W2 (for example, the width in the X direction) after passing through the aperture 5 (FIG. 11B). . Thereby, the difference ΔW = W1−W2 between the ion beam width W1 and the ion beam width W2 can be calculated. This difference ΔW indicates the degree of expansion of the ion beam 3 expanded due to the expansion of the slit portion of the extraction electrode 2. Therefore, the expanded state of the ion beam 3 can be more accurately reflected by using the difference ΔW as a parameter indicating the ion beam shape in the first and third embodiments.

  That is, with the method described in the first embodiment, the relationship between the difference ΔW and the breakdown rate of the charge-up evaluation element such as the antenna MOS is acquired in advance. Then, based on the correspondence relationship, a predicted value Y of the breakdown rate of the charge-up evaluation element corresponding to the measured difference ΔW is calculated. Then, the ion beam shape is adjusted so that the predicted value Y is equal to or lower than the preset upper limit management standard Yc. In the method described in the third embodiment, the width of the ion beam 3 is adjusted when the difference ΔW exceeds the threshold value ΔWc acquired in advance through experiments or the like.

  As described above, by using the difference ΔW as a parameter, the state of the electron beam stripping of the ion beam 3 due to the expansion of the ion beam 3 and the state of beam irradiation at the periphery of the opening of the aperture 5 are more accurately reflected. be able to. During the ion implantation process, the Faraday cup 16 and the Faraday cup 10 are both located outside the orbit of the ion beam 3.

  On the other hand, in an ion implantation apparatus in which an electrostatic lens is not provided in the beam line and the beam line length is shortened for the purpose of suppressing the diffusion of the ion beam 3 as much as possible, the Faraday cup 16 is interposed between the mass analyzer 4 and the aperture 5. It is difficult to provide the layout. In such an apparatus, the aperture 5 may be provided to be movable.

  FIG. 12 is a schematic configuration diagram showing a modification of the ion implantation apparatus of the present embodiment. As shown in FIGS. 12A and 12B, in the ion implantation apparatus 500, the aperture 5 is disposed so as to be movable between a position outside the orbit of the ion beam 3 and a position inserted in the orbit. ing. Other configurations are the same as those of the ion implantation apparatus 100 described in the first embodiment. In FIG. 12, the control system is not shown.

  In the ion implantation apparatus 500, as shown in FIG. 12A, at the time of setup, the aperture 5 is first moved to a position outside the orbit of the ion beam 3, and the Faraday cup 10 is inserted into the orbit of the ion beam 3. Then, the Faraday cup 10 measures the ion beam width W3 (for example, the width in the X direction) when there is no aperture 5. After that, the aperture 5 is inserted into the trajectory of the ion beam 3, and the Faraday cup 10 measures the ion beam width W4 (for example, the width in the X direction) after passing through the aperture 5 (FIG. 12B). Thereby, the difference ΔW2 = W3−W4 between the ion beam width W3 and the ion beam width W4 can be calculated. The difference ΔW2 indicates the degree of expansion of the ion beam 3 expanded due to the expansion of the slit portion of the extraction electrode 2, similarly to the above-described difference ΔW. Therefore, by using the difference ΔW2 as a parameter indicating the ion beam shape in the first and third embodiments described above, the expanded state of the ion beam 3 can be more accurately reflected. During the ion implantation process, the aperture 5 is inserted into the trajectory of the ion beam 3 and the Faraday cup 10 is located outside the trajectory of the ion beam 3.

  As described above, according to the present embodiment, charge-up suppression and particle suppression can be performed more accurately. As a result, it is possible to more accurately avoid a decrease in product yield and improve the apparatus operating rate. In the present embodiment, the measurement order of the ion beam widths W1 and W2 and the ion beam widths W3 and W4 is not limited at all.

  As described above, according to the present invention, in the ion implantation apparatus, it is possible to determine in real time whether or not charge-up occurs and further whether or not particles are generated. In addition, the ion implantation apparatus can be operated for as long as possible in a state where charge-up and particle generation are suppressed within a certain range. As a result, a decrease in product yield can be suppressed, and the apparatus operating rate can be significantly improved.

  The present invention is not limited to the embodiments described above, and various modifications and applications are possible within the scope of the effects of the present invention.

  The present invention has effects of suppressing charge-up and reducing particle generation, and is useful as an ion implantation apparatus and a control method therefor.

1 is a schematic configuration diagram showing an ion implantation apparatus according to a first embodiment of the present invention. Explanatory drawing showing the generation mechanism of charge-up caused by enlargement of the slit part of the extraction electrode Diagram showing correspondence between ion beam width and antenna MOS breakdown rate The flowchart which shows the control method of the ion implantation apparatus in the 1st Embodiment of this invention. The schematic block diagram which shows the ion implantation apparatus in the 2nd Embodiment of this invention. Diagram showing correspondence between disk current and antenna MOS breakdown rate The flowchart which shows the control method of the ion implantation apparatus in the 2nd Embodiment of this invention. Schematic configuration diagram showing an ion implantation apparatus according to a third embodiment of the present invention. The figure which shows the correspondence of beam irradiation accumulation time and the number of particles increase The flowchart which shows the control method of the ion implantation apparatus in the 3rd Embodiment of this invention. The schematic block diagram which shows the ion implantation apparatus in the 4th Embodiment of this invention. The schematic block diagram which shows the modification of the ion implantation apparatus in the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ion source 2 Extraction electrode 3 Ion beam 4 Mass analysis part 5 Aperture 6 Electron shower 7 Wafer 8 Wafer holding part 9 Disc current measurement part 10 Faraday cup (immediately after an aperture)
11 Faraday cup (wafer injection part)
12 Device controller 16 Faraday cup (just before the aperture)
21, 31 Destruction rate prediction unit 22, 32 Determination unit 41 Particle monitoring unit

Claims (24)

In an ion implantation apparatus having a mechanism for causing an ion beam extracted from an ion source and subjected to mass analysis to enter a substrate through an aperture and to supply electrons to the ion beam that has passed through the aperture.
Means for obtaining a physical quantity having a correlation with a breakdown rate of the charge-up evaluation element;
Means for predicting the destruction rate of the charge-up evaluation element corresponding to the acquired physical quantity based on the correspondence relationship between the physical quantity and the destruction rate acquired in advance;
Means for adjusting the physical quantity to a state in which the breakdown rate of the charge-up evaluation element is equal to or less than the threshold value in the corresponding relationship when the predicted breakdown rate of the charge-up evaluation element exceeds a preset threshold; ,
An ion implantation apparatus comprising:   The ion implantation apparatus according to claim 1, wherein the physical quantity is an ion beam shape after passing through the aperture.   The ion implantation apparatus according to claim 2, wherein when the predicted breakdown rate of the charge-up evaluation element exceeds a preset threshold, the ion beam shape is adjusted by suppressing diffusion of the ion beam.   The ion implantation apparatus according to claim 1, wherein the physical quantity is a current flowing between a substrate and a ground potential during ion implantation.   The ion implantation apparatus according to claim 4, wherein when the predicted breakdown rate of the charge-up evaluation element exceeds a preset threshold value, the current is adjusted by increasing an electron supply amount to the ion beam. . Means for obtaining an accumulated time during which the ion beam irradiates a peripheral edge of the aperture of the aperture;
Means for stopping the ion implantation process when the accumulated time exceeds a preset threshold;
The ion implantation apparatus according to claim 1, further comprising: Means for obtaining an accumulated time during which the ion beam irradiates a peripheral edge of the aperture of the aperture;
A means for issuing a warning when the accumulated time is not more than a preset threshold and is a positive value;
The ion implantation apparatus according to claim 1, further comprising:   The ion implantation apparatus according to claim 6 or 7, wherein the integrated time is calculated from an ion beam shape after passing through the aperture and an ion beam irradiation time.   The ion implantation apparatus according to claim 6 or 7, wherein the integrated time is calculated from a difference between an ion beam shape immediately before passing through the aperture, an ion beam shape after passing through the aperture, and an ion beam irradiation time. The aperture is movably disposed between a position inserted in a trajectory of the ion beam and a position outside the trajectory;
The accumulated time is determined by the difference between the ion beam shape when the aperture is at a position outside the orbit and the ion beam shape when the aperture is at the position inserted in the orbit, and the ion beam irradiation time. The ion implantation apparatus according to claim 6 or 7, wherein the ion implantation apparatus is calculated.   The ion implantation apparatus according to claim 1, wherein the physical quantity is a difference between an ion beam shape immediately before passing through the aperture and an ion beam shape after passing through the aperture. The aperture is movably disposed between a position inserted in a trajectory of the ion beam and a position outside the trajectory;
2. The ion according to claim 1, wherein the physical quantity is a difference between an ion beam shape when the aperture is at a position outside the orbit and an ion beam shape when the aperture is at a position inserted in the orbit. Injection device. In a control method of an ion implantation apparatus having a mechanism for causing an ion beam extracted from an ion source and subjected to mass analysis to enter a substrate through an aperture and to supply electrons to the ion beam that has passed through the aperture,
Obtaining a physical quantity having a correlation with the breakdown rate of the charge-up evaluation element;
Predicting the destruction rate of the charge-up evaluation element corresponding to the acquired physical quantity based on the correspondence relationship between the physical quantity and the destruction rate acquired in advance;
When the predicted breakdown rate of the charge-up evaluation element exceeds a preset threshold value, the physical quantity is adjusted to a state in which the breakdown rate of the charge-up evaluation element is equal to or less than the threshold value in the correspondence relationship; ,
A method for controlling an ion implantation apparatus, comprising:   The method of controlling an ion implantation apparatus according to claim 13, wherein the physical quantity is an ion beam shape after passing through the aperture.   15. The ion implantation apparatus according to claim 14, wherein when the predicted breakdown rate of the charge-up evaluation element exceeds a preset threshold value, the ion beam shape is adjusted by suppressing diffusion of the ion beam. Control method.   The method of controlling an ion implantation apparatus according to claim 13, wherein the physical quantity is a current flowing between a substrate and a ground potential during ion implantation.   The ion implantation apparatus according to claim 16, wherein when the predicted breakdown rate of the charge-up evaluation element exceeds a preset threshold, the current is adjusted by increasing an electron supply amount to the ion beam. Control method. Obtaining an accumulated time during which the ion beam irradiates a peripheral edge of the aperture of the aperture; and
If the integration time exceeds a preset threshold, stopping the ion implantation process;
The method of controlling an ion implantation apparatus according to claim 13, further comprising: Obtaining an accumulated time during which the ion beam irradiates a peripheral edge of the aperture of the aperture; and
A warning is issued when the accumulated time is a predetermined threshold value or less and a positive value; and
The method of controlling an ion implantation apparatus according to claim 13, further comprising:   The method of controlling an ion implantation apparatus according to claim 18 or 19, wherein the integrated time is calculated from an ion beam shape after passing through the aperture and an ion beam irradiation time.   The control of the ion implantation apparatus according to claim 18 or 19, wherein the integration time is calculated by a difference between an ion beam shape immediately before passing through the aperture, an ion beam shape after passing through the aperture, and an ion beam irradiation time. Method. The aperture is movable between a position inserted in the trajectory of the ion beam and a position outside the trajectory;
The accumulated time is determined by the difference between the ion beam shape when the aperture is at a position outside the orbit and the ion beam shape when the aperture is at the position inserted in the orbit, and the ion beam irradiation time. 20. The ion implantation control method according to claim 18 or 19, which is calculated.   The method of controlling an ion implantation apparatus according to claim 13, wherein the physical quantity is a difference between an ion beam shape immediately before passing through the aperture and an ion beam shape after passing through the aperture. The aperture is movable between a position inserted in the trajectory of the ion beam and a position outside the trajectory;
The ion according to claim 13, wherein the physical quantity is a difference between an ion beam shape when the aperture is in a position outside the orbit and an ion beam shape when the aperture is in a position inserted in the orbit. Control method of injection device.

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