JPH08115701A - Ion implantation condition abnormality detecting method in ion implanting device - Google Patents

Abstract

PURPOSE: To accurately detect the kind of an ion in an ion beam and abnormality of energy by calculating the radius of curvature of the ion beam in an energy analysis magnet and checking whether the calculated value is within an allowable range or not. CONSTITUTION: Energy of an ion beam is decided. Drawer voltage VE, accelerated voltage VA, decelerated voltage VD, each flux density of mass and energy analysis magnets 12, 24 are measured. The radius of curvature RF of the ion beam 8 is calculated under the condition of flux density of the magnet 24, the number of masses and the number of valences of ions, and voltage VE+VA or VD of the beam 8. The radius of curvature RF is compared with the radius of curvature R0 of the reference calculated and registered previously when each condition is adequately adjusted. Whether the measured and compared results are within each specified range or not is checked before and after implantation of the ion beam 8 into a target 32. A controller 50 displays the result on a display 54 and controls each device. As a result, the kind of an ion and abnormality of energy are accurately detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an implantation condition abnormality detection method for detecting abnormality of ion species and energy of an ion beam in an ion implantation apparatus for irradiating a target with an ion beam for ion implantation.

[0002]

2. Description of the Related Art FIG. 1 is a schematic view showing an example of an ion implantation apparatus to which the present invention is applied. This device magnetically scans the ion beam 8 in parallel, and at the same time, the target 3
It is a so-called hybrid parallel scan type ion implanter that mechanically scans 2.

This ion implantation apparatus is provided on an ion source 2 for extracting an ion beam 8 and on the downstream side of the ion source 2, and a specific ion species (from this) is extracted from the ion beam 8 extracted from the ion source 2. The ion species is specified by the mass number and the valence) and is extracted from the mass analysis magnet 12, and the ion provided from the mass analysis magnet 12 is provided on the downstream side of the mass analysis magnet 12. Accelerator tube 14 for accelerating or decelerating the beam 8.
Of the energy analysis magnet 24, which is provided on the downstream side of the acceleration tube 14 and selects and derives ions of a specific energy from the ion beam 8 derived from the acceleration tube 14. The same energy analysis magnet 24 is provided on the downstream side.
A scanning magnet 26 that magnetically scans the ion beam 8 derived from the one-dimensional (along the paper surface in the illustrated example).
The ion beam 8 that is provided on the downstream side of the scanning magnet 26 is bent back so as to be parallel to the reference axis 30 by colliding with the scanning magnet 26. A beam collimating magnet 28 that performs parallel scanning of the beam 8 and a target (for example, a target within the irradiation region of the ion beam 8 that is provided on the downstream side of the beam collimating magnet 28 and is derived from the beam collimating magnet 28). A scanning mechanism 34 that mechanically scans the wafer 32 in a direction substantially orthogonal to the scanning direction of the ion beam 8 in the scanning magnet 26 (in the illustrated example, in the front-back direction of the paper). The target 32 is irradiated with the ion beam 8 to perform ion implantation.

The ion source 2 is equipped with a plasma generation unit 4 for generating plasma by ECR discharge, for example, and an extraction electrode 6 for extracting an ion beam 8 by the action of an electric field from the plasma generation unit 4. The extraction voltage V _E is applied from the DC extraction power source 10 to the side.

The accelerating tube 14 has a multi-stage electrode 16, and the accelerating voltage V _A is applied to both ends of the accelerating tube 20 from a DC accelerating power source 20 with the upstream side being the positive side in the accelerating mode. It The most downstream electrode 16 is grounded. In the case of the deceleration mode, the acceleration power supply 20 is disconnected and the former is set to the positive side between the plasma generation unit 4 of the ion source 2 and the ground, as shown by the chain double-dashed line in FIG. The deceleration mode voltage V _D is applied from the power supply 22.

The scanning mechanism 34 includes a reversible motor 36 provided outside the vacuum container 46, a reversible motor 38 attached to its rotation shaft 37, and its rotation shaft (not shown). An arm 40 attached to the motor 40, a motor 42 attached to the tip of the arm 40, and a holder 44 attached to the rotation shaft (not shown) of the motor 42 for holding the target 32. The angle of incidence of the ion beam 8 on the target 32 can be changed by rotating the motor 38 and the like as indicated by an arrow 61 by the motor 36. The motor 38 can rotate the arm 40 as shown by an arrow 62 to mechanically scan the target 32 in the front-back direction of the paper. The target 42 can be rotated during the injection by rotating the holder 44 as indicated by the arrow 63 by the motor 42.

Further, the ion implanter comprises a controller 50 for controlling the entire ion implanter, and a man-machine controller 52 connected to the controller 50 for performing input / output with an operator. . The man-machine controller 52 has a display device 54.

With the above structure, the target 32 is irradiated with the ion beam 8 of desired ion species and energy while being parallel-scanned, and the target 32 is mechanically scanned to uniformly ion-implant the entire surface of the target 32. be able to.

Note that the electric scanning of the ion beam 8 is magnetically performed by using the scanning magnet 26 and the beam collimating magnet 28 because of the voltage applied to the scanning electrodes as in the electrostatic scanning. This is because it is possible to prevent the electrons in the ion beam 8 from being deprived and the space charge of the ions to increase, so that the ion beam can be prevented from diverging. This is particularly effective when handling a large amount of ion beams 8 with low energy. Is remarkable.

Further, the beam collimating magnet 28 is provided to scan the ion beam 8 in parallel.
This is because the incident angle (that is, the implantation angle) of the ion beam 8 can be made constant over the entire surface of.

[0011]

Of the implantation conditions in the above-described ion implantation apparatus, the main implantation conditions related to the ion beam 8 include the ion species and energy of the ion beam 8 and the target 32. There is an injection volume. The ionic species is specified by the mass number and valence of the ions.

It is necessary to avoid erroneous injection in which such injection conditions are incorrect. In particular, in a production machine that processes a large number of targets 32, erroneous injection causes a great deal of damage. Therefore, it is necessary to make every effort to prevent erroneous injection.

Of the above-mentioned implantation conditions, the implantation amount can be easily measured by the product of the beam current flowing through the target 32 and the implantation time, so that the abnormal implantation amount can be easily detected.

However, it is not easy to reliably detect that the ion species and energy of the ion beam 8 deviate from the desired one.

That is, regarding the energy of the ion beam 8, conventionally, the extraction voltage V _E , the acceleration voltage V _A, and the deceleration mode voltage V _D that determine the energy are determined by a voltage composed of a voltage measuring resistor and a D / A converter. Each was measured by the measurement system. Among them, especially for the accelerating voltage V _A , two voltage measuring systems were provided independently of each other, and it was softly checked that the difference between the measured data of the two was within a certain range. No check was performed on the voltage V _E and the deceleration mode voltage V _D.

Therefore, even if the extraction voltage V _E and the deceleration mode voltage V _D are measured, there is no guarantee that they are correct. Further, even if two voltage measuring systems such as the accelerating voltage V _A are provided, if the two systems are similarly displaced, it was not possible to detect it.

On the other hand, as for the ion species, conventionally, for example, as shown in Table 1, the mass number of ions, the valence number of ions and the magnetic flux density of the mass analysis magnet 12 are combined for each extraction voltage V _E. A reference mass table is registered in advance in the control device 50 or the like, and the current value of the magnetic flux density in the mass analysis magnet 12 (that is, the value at the time of checking. The same applies hereinafter) corresponds to the mass table ( That is, it was checked whether the magnetic flux density was within the permissible range (for the corresponding extraction voltage V _E , mass number and valence).

[0018]

[Table 1]

However, since the validity of the data registered as the mass table has not been checked, if the registered data is abnormal, that is, if incorrect data is registered for some reason, a correct check is performed. There was a problem that I could not.

Therefore, the main object of the present invention is to provide an implantation condition abnormality detection method capable of correctly detecting abnormality of ion species and energy of an ion beam.

[0021]

In order to achieve the above object, the first injection condition abnormality detection method of the present invention is a value at the time of checking the magnetic flux density in the energy analysis magnet before and during injection into a target. And the ion beam mass number, valence number, and total applied voltage to the ion beam at that time, the radius of curvature of the ion beam in the energy analysis magnet is calculated, and the radius of curvature is a predetermined allowable value with respect to the reference value. It is characterized by comprising a step of checking a radius of curvature in the energy analysis magnet for checking whether or not it is within the range.

According to a second method for detecting an abnormal implantation condition of the present invention, the value at the time of checking the extraction voltage applied to the ion source for extracting the ion beam and the value applied to the acceleration tube for accelerating the ion beam. The acceleration voltage or the value at the time of checking the deceleration mode voltage applied for decelerating the ion beam between the ion source and the accelerating tube is within a predetermined allowable range for each set value. , The energy determinant checking step to check before and during implantation into the target, and for each set value of the extraction voltage, the value at the time of checking the magnetic flux density in the mass analysis magnet for the mass number and valence of the ions at the time of the check , The mass spectrometer checks before and during injection into the target to see if it is within predetermined tolerances for that reference value. In the magnetic flux density check process in the net, before and during the injection into the target, the value at the time of checking the magnetic flux density in the energy analysis magnet, the mass number of ions at that time, the valence and the total applied voltage to the ion beam Based on this, a curvature radius check step in the energy analysis magnet for calculating the radius of curvature of the ion beam in the energy analysis magnet and checking whether the radius of curvature is within a predetermined allowable range with respect to the reference value. It is characterized by being provided.

According to a third method for detecting an abnormal implantation condition of the present invention, the value at the time of checking the magnetic flux density in the energy analysis magnet before and during the implantation into the target, and the mass number, valence number and ion of the ion at that time. The first radius of curvature of the ion beam in the energy analysis magnet is calculated based on the total applied voltage to the beam, and whether or not the first radius of curvature is within a predetermined allowable range with respect to the reference value. Checking the radius of curvature in the energy analysis magnet, and the value at the time of checking the magnetic flux density in the beam parallelizing magnet before and during the injection into the target,
The second radius of curvature of the ion beam in the beam collimating magnet is calculated based on the mass number of ions, the valence, and the total applied voltage to the ion beam, and the second radius of curvature and the first radius of curvature are calculated. The radius of curvature of the beam collimating magnet is checked to determine whether the ratio is within a predetermined allowable range with respect to the reference value.

According to a fourth method for detecting abnormal implantation conditions of the present invention, the value at the time of checking the extraction voltage applied to the ion source for extracting the ion beam and the value applied to the acceleration tube for accelerating the ion beam. The acceleration voltage or the value at the time of checking the deceleration mode voltage applied for decelerating the ion beam between the ion source and the accelerating tube is within a predetermined allowable range for each set value. , The energy determinant checking step to check before and during implantation into the target, and for each set value of the extraction voltage, the value at the time of checking the magnetic flux density in the mass analysis magnet for the mass number and valence of the ions at the time of the check , The mass spectrometer checks before and during injection into the target to see if it is within predetermined tolerances for that reference value. In the magnetic flux density check process in the net, before and during the injection into the target, the value at the time of checking the magnetic flux density in the energy analysis magnet, the mass number of ions at that time, the valence and the total applied voltage to the ion beam In the energy analysis magnet, based on which the first radius of curvature of the ion beam in the energy analysis magnet is calculated, and whether or not the first radius of curvature is within a predetermined allowable range with respect to the reference value Based on the radius-of-curvature checking step, the value at the time of checking the magnetic flux density in the beam collimating magnet before and during the implantation into the target, the mass number of ions at that time, the valence and the total applied voltage to the ion beam. The second bend of the ion beam in the beam collimating magnet. A beam collimating magnet for calculating a radius, determining a ratio between the second radius of curvature and the first radius of curvature, and checking whether the ratio is within a predetermined allowable range with respect to the reference value. And a radius of curvature checking step in.

[0025]

EXAMPLES The most strict example of the implantation condition abnormality detection method in the ion implantation apparatus shown in FIG. 1 will be mainly described below.

The injection condition abnormality detection method of this embodiment is as follows.
An energy determining factor checking step, a magnetic flux density checking step in a mass analysis magnet, a curvature radius checking step in an energy analysis magnet, and a curvature radius checking step in a beam collimating magnet are provided. The processes such as data registration, calculation, and comparison in these checking steps are performed in the control device 50 and the man-machine controller 52, for example. Each of these steps will be described in detail below.

(1) Energy deciding factor checking process

In this checking process, the extraction voltage V _E
And the current values of the acceleration voltage V _A (in the acceleration mode) or the current values of the extraction voltage V _E and the deceleration mode voltage V _D (in the deceleration mode) are within a predetermined allowable range for the respective set values. Check whether each is in. The current value is the current value at the time of checking (hereinafter the same).

As described above, the extraction voltage V _E is applied from the extraction power source 10 to the ion source 2, more specifically, between the plasma generation part 4 and the extraction electrode 6 to extract the ion beam 8. Voltage. Acceleration voltage V _A
As described above (as shown in FIG. 1), is a voltage applied from both ends of the accelerating tube 14 from the accelerating power source 20 for accelerating the ion beam 8. In the acceleration mode, the total applied voltage to the ion beam 8 is V _E + V _A , which determines the energy of the ion beam 8. As described above (as indicated by the chain double-dashed line in FIG. 1), the deceleration mode voltage V _D is the same as that of the ion source 2 in the deceleration mode.
The voltage applied from the deceleration mode power supply 22 for decelerating the ion beam 8 between the plasma generation unit 4 and the ground end of the acceleration tube 14. At this time, the acceleration power supply 20 is disconnected. In the deceleration mode, the total applied voltage to the ion beam 8 is V _D , which determines the energy of the ion beam 8.

Specifically, each voltage V _E , V _A and V _D
, The allowable range for each set value is ±
It is set as α ₁ kV, ± α ₂ kV, and ± α ₃ kV, and it is normal if the current values of the respective voltages V _E , V _A, and V _D are within the permissible range for a certain period of time or not, and it is abnormal. . The requirement for a certain period of time or more is to ignore momentary fluctuations in values (the same applies below). However, in the deceleration mode, since the extraction voltage V _E is not related to the energy of the ion beam 8, it is not necessary to check the extraction voltage V _E.

Such a check is performed both before and during the implantation of the target 32.

That is, the above-mentioned check is carried out immediately before the start of injection, and in the case of an abnormality, "injection is not possible" and an error message is displayed on the display device 54 of the man-machine controller 52. If it is normal, the process proceeds to the injection process. The “implantation impossible” means that the control sequence toward the ion implantation does not proceed further in the control device 50 (the same applies hereinafter).

Further, the above-mentioned check is carried out during the injection, and in the case of an abnormality, it is set to "hold" and an error message is displayed on the display device 54. If normal, continue the injection process. “Hold” is to extract the ion beam 8 from the ion source 2 but deflect it to a position where it does not enter the target 32, and stop the mechanical scanning of the target 32 (the same applies hereinafter).

By carrying out the above-mentioned check, the abnormalities of the respective voltages V _E , V _A and V _{D which} cause the abnormal energy of the ion beam 8 can be detected before and during the implantation. As a result, the energy abnormality of the ion beam 8 can be detected.

Further, when the check result is abnormal, the above-described "injection impossible" and "hold" processing is performed, so that the target 32 is swiftly discharged before the injection and swiftly injected. On the other hand, it is possible to prevent abnormal injection of wrong energy.

(2) Magnetic flux density checking step in mass analysis magnet

In this checking step, for each set value of the extraction voltage V _E , the current value of the magnetic flux density in the mass analysis magnet 12 with respect to the mass number and valence of the ions at the time of checking is within a predetermined allowable range with respect to the reference value. It is checked whether or not it is within the range using mass table data. The current value of the magnetic flux density in the mass analysis magnet 12 is obtained by using, for example, a Hall probe (not shown) which is conventionally embedded in the mass analysis magnet 12.

As shown in Table 2, an example of mass table data is that, for each extraction voltage V _E , the mass number of ions, the valence number of ions, the magnetic flux density in the mass analysis magnet 12,
The allowable upper limit value and the allowable lower limit value are combined.

[0039]

[Table 2]

Further, in this embodiment, the validity of the mass table itself is also checked. Specifically, the following checks are performed.

For each mass number and valence of each extraction voltage (that is, for each vertical column of each mass table), it is checked whether or not the following equation is satisfied.

[0042]

## EQU1 ## B _l ≤B _s ≤B _u Here, B _s is the magnetic flux density, B _u is the allowable upper limit thereof, and B _l
Is the lower limit of the tolerance.

Mutual check of all data in each mass table is performed. That is, the radius of curvature R [m] of the ion beam 8 in the mass analysis magnet 12 is expressed by the following equation.

[0044]

## EQU2 ## R = (1 / B) √ (2 mV / q) where B is the magnetic flux density [T] and m is the ion mass number [k
g] and q are the charge amount [C] of the ions, and V is the ion beam 8
Is the total applied voltage [V] to the. Further, when the mass number of ions is M and the mass of protons m _p , m = Mm _p . Furthermore, if the valence of the ion is n and the elementary charge is e, then q = n
It is e.

Further, V [V] = V ₁ [kV] × 10 ³ ,
Assuming that B [T] = B ₁ [G] × 10 ⁻⁴ , this voltage V ₁ ,
When the above equation 2 is expressed using the magnetic flux density B _{1, the} mass number M, and the valence number n, the following equation is obtained.

[0046]

## EQU3 ## R = 45.66 (1 / B ₁ ) √ (MV ₁ / n)

Therefore, for all data in each mass table, the radius of curvature R is calculated from Equation 3, and all of the values are ± x of the reference value (specifically, the set value of the radius of curvature of the mass analysis magnet 12). Check whether it is within the tolerance of ₁ %. Incidentally, this x ₁ is set in the man-machine controller 52, for example.

The above-mentioned check of the correctness of the mass table is carried out when the mass table data is set and registered. If even one data is abnormal, registration of the mass table data is disabled and an error message is displayed on the display device 54 of the man-machine controller 52.

By checking the correctness of the mass table as described above, it is possible to prevent abnormal data from being registered in the mass table. Therefore, in the mass spectroscopic magnet 12 using the mass table data. The reliability of checking the magnetic flux density is further enhanced.

The check of the magnetic flux density in the mass analysis magnet 12 using the mass table data is performed both before and during the injection into the target 32. That is, the above check is carried out immediately before the start of injection,
In the case of an abnormality, “Injection is not allowed” and the display device 54
Error message is displayed. If it is normal, the process proceeds to the injection process. In addition, perform the above checks during injection,
In the case of abnormality, the display device 54
Error message is displayed. If normal, continue the injection process.

By checking the magnetic flux density in the mass analysis magnet 12 as described above, the condition that the ion beam 8 of the correct ion species, that is, the correct mass number and valence number is derived from the mass analysis magnet 12 is established. Since it can be detected before and during the injection, an abnormality of the ionic species can be detected.

Further, when the check result is abnormal, the above-described "injection impossible" and "hold" processing is performed, so that the target 32 is promptly displayed before the injection and promptly during the injection. On the other hand, it is possible to prevent the abnormal implantation of the wrong ionic species.

(3) Curvature radius check process in energy analysis magnet

In this checking step, based on the current value of the magnetic flux density in the energy analysis magnet 24, the mass number and valence of the ions at that time, and the total applied voltage to the ion beam 8, the ion beam in the energy analysis magnet 24 is calculated. The radius of curvature R _F of 8 is calculated, and it is checked whether or not the radius of curvature is within a predetermined range with respect to the reference value. The current value of the magnetic flux density in the energy analysis magnet 24 is measured using, for example, a Hall probe (not shown) embedded in the energy analysis magnet 24 in the related art. As described above, the total applied voltage to the ion beam 8 is the sum of the extraction voltage V _E and the acceleration voltage V _A (that is, V _E + V _A ) in the acceleration mode,
In the deceleration mode, it is the deceleration mode voltage V _D.

Specifically, the ion implantation apparatus is adjusted to a preferable state, and the measured values of the ion mass number, valence number, total applied voltage to the ion beam 8 and magnetic flux density at the energy analysis magnet 24 at that time are measured. Collect one set and register this as data. Table 3 shows an example thereof. Then, by substituting this data into M, n, V ₁ and B ₁ of the equation 3, the radius of curvature R at that time is obtained, and this is set as the reference value R _{0 of the} radius of curvature in the energy analysis magnet.
By the way, the data such as the above-mentioned equation 3 is used, for example, in the controller 5
0 or registered in the man-machine controller 52.

[0056]

[Table 3]

Then, based on the value of the magnetic flux density in the energy analysis magnet 24 at the time of checking, the mass number and valence number of ions at that time, and the total applied voltage to the ion beam 8, the radius of curvature R _F Is _calculated and compared with the reference value R ₀ . Specifically, it is checked whether or not the radius of curvature R _F is within an allowable range of ± x ₂ % with respect to the reference value R ₀ . Incidentally, this x ₂ is set in the man-machine controller 52, for example.

Prior to such a check, in this embodiment, in order to confirm the validity of the registration data itself as shown in Table 3 above, the reference value R _{0 of the} radius of curvature in the energy analysis magnet 24 obtained from the data is obtained. However, based on the original design value, it is confirmed whether or not it is within the range of ± x ₂ %. This confirmation is performed when the above data is registered. In the case of abnormality, the registration of the data is disabled and an error message is displayed on the display device 54.

By checking the validity of the registration data as described above, it is possible to prevent abnormal data from being registered. Therefore, the curvature radius check in the energy analysis magnet 24 is performed using the registration data. Will be more reliable.

The radius of curvature R _F is checked both before and during implantation into the target 32. That is, the above check is performed immediately before the start of injection, and in the case of an abnormality, "injection is not possible" is performed and an error message is displayed on the display device 54. If it is normal, the process proceeds to the injection process. Further, the above check is carried out during the injection, and in the case of an abnormality, it is set to "hold" and an error message is displayed on the display device 54. If normal, continue the injection process.

As can be seen from equation 3, the radius of curvature R _F is information on the mass number and valence number of ions (ie ion species) and the total applied voltage to the ion beam 8 (ie energy of the ion beam 8). Therefore, by performing the above check, it is possible to correctly detect the abnormality of the ion species and energy of the ion beam 8 before and during the injection only by performing the above check.

Further, when the check result is abnormal, the above-described "injection impossible" and "hold" processing is performed, so that the target 32 can be immediately detected before the injection and promptly during the injection. On the other hand, it is possible to prevent the abnormal implantation of erroneous ion species or energy.

(4) Radius of curvature check process in the beam collimating magnet

In this checking step, the current value of the magnetic flux density in the beam collimating magnet 28, the mass number and valence of the ions at that time, and the total applied voltage to the ion beam 8 are applied to the beam collimating magnet 28. The radius of curvature R _C of the ion beam 8 is calculated, and the ratio between the radius of curvature R _C and the radius of curvature R _F of the energy analysis magnet 24 is calculated. Is this ratio within a predetermined allowable range with respect to the reference value? Whether or not the target 32 is injected before and during the injection is checked.

Specifically, the beam collimating magnet 28
The current value of the magnetic flux density at is measured using, for example, a Hall probe (not shown) conventionally embedded in the beam collimating magnet 28, and the mass number and valence of ions at that time and the total application to the ion beam 8. Based on the voltage, the radius of curvature R _C is obtained from the equation 3, and the ratio R _C / R _F of this radius of curvature R _C and the radius of curvature R _F of the energy analysis magnet 24 is obtained, and this ratio is the reference value K. Check if it is within the tolerance of ± x ₃ % of. The value of this reference value K is, for example, the ratio of the design values of both radii of curvature R _F and R _C. Incidentally, this K and the above x ₃ are set in the man-machine controller 52, for example.

The radius of curvature R _C is checked both before and during the implantation of the target 32. That is, the above check is performed immediately before the start of injection, and in the case of an abnormality, "injection is not possible" is performed and an error message is displayed on the display device 54. If normal, the injection process is transferred to the process. Further, the above check is carried out during the injection, and in the case of an abnormality, it is set to "hold" and an error message is displayed on the display device 54. If normal, continue the injection process.

[0067] to be the radius of curvature R _C, as in the case of the curvature radius R _F, as can be seen from Equation 3, the mass number and valence of ions (i.e. ionic species), as well as the total voltage applied to the ion beam 8 Since the information on the ion beam 8 (that is, the energy of the ion beam 8) is included, by performing the above-described check, the ion parallelism of the ion beam 8 and the abnormal energy of the ion beam 8 are injected even in the part of the beam parallelizing magnet 28. It can be detected correctly before and during injection.

Further, when the check result is abnormal, by performing the processing of "implantation impossible" and "hold" as described above, the target 32 is swiftly displayed before the injection and promptly during the injection. On the other hand, it is possible to prevent the abnormal implantation of erroneous ion species or energy.

Since any of the above checks is to check the correctness in terms of software, unlike the conventional case where the voltage measurement system has two systems, a new check process is required. There is also an advantage that it is not necessary to add a special device (hardware).

It should be noted that the more the steps of the energy deciding factor checking step, the magnetic flux density checking step in the mass analysis magnet, the curvature radius checking step in the energy analysis magnet, and the curvature radius checking step in the beam collimating magnet are performed, This is more preferable because the check is repeated and the check becomes strict, but even if only the curvature radius check step in the energy analysis magnet is performed, the ion species and energy of the ion beam 8 are abnormal due to the reason as described above. It can be detected correctly before and during injection.

The configuration of the ion implantation apparatus downstream of the energy analysis magnet 24 is not limited to the example shown in FIG. For example, an ion implanter of a simple hybrid scan type in which the beam collimating magnet 28 is stopped and the ion beam 8 is not scanned in parallel may be used, or the scanning magnet 26 and the beam collimating magnet 28 may be stopped and the ion beam 8 is stopped. It is also possible to use a mechanical scan type ion implantation apparatus in which the target 32 is mounted on a rotating and translating wafer disk and mechanically scanned without scanning. In these cases, since the beam collimating magnet 28 does not exist, the above-described fourth checking step, that is, the curvature radius checking step in the beam collimating magnet 28 is not performed.

[0072]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, the radius of curvature of the energy analysis magnet includes information on the mass number and valence number of ions (ie ion species) and the total applied voltage to the ion beam (ie ion beam energy). Is included, anomalies in ion species and energy of the ion beam can be correctly detected before and during the implantation.

Moreover, such detection can be performed without adding a new device for performing the checking process.

According to the second aspect of the invention, since the abnormality of each voltage that causes the energy abnormality of the ion beam can be detected before and during the implantation by the energy deciding factor checking step, the ion beam of the ion beam can be detected. Energy anomalies can be detected.

Before the injection and the injection, it is confirmed that the conditions for deriving the ion beam of the correct ion species, that is, the correct mass number and valence number from the mass analysis magnet are not satisfied by the magnetic flux density check process in the mass analysis magnet. Since it can be detected in the inside, an abnormality of the ionic species can be detected.

Further, according to the curvature radius check process in the energy analysis magnet, the mass radius and valence number (ie, ion species) of ions and the total applied voltage (ie, energy of ion beam) to the ion beam are found in the radius of curvature in the energy analysis magnet. Information of the ion beam, it is possible to detect abnormalities in ion species and energy of the ion beam before and during implantation.

Since the energy deciding factor checking step, the curvature radius checking step in the mass analysis magnet, and the curvature radius checking step in the energy analysis magnet are performed in a very strict and overlapping manner, the ion beam Ion species and energy anomalies can be detected with very high reliability.

Moreover, such detection can be performed without adding a new device for performing the checking process.

According to the third aspect of the invention, the mass radius and valence number (ie, ion species) of the ions and the total applied voltage to the ion beam are determined in the radius of curvature of the energy analysis magnet by the step of checking the radius of curvature of the energy analysis magnet. Since the information of (ie, the energy of the ion beam) is included, it is possible to detect the abnormality of the ion species and energy of the ion beam before and during the implantation.

Further, by the curvature radius checking process in the beam collimating magnet, as in the curvature radius checking process in the energy analyzing magnet, abnormalities in ion species and energy of the ion beam are injected also in the beam collimating magnet portion. It can be detected before and during injection.

Due to the curvature radius checking process in the energy analysis magnet and the curvature radius checking process in the beam collimating magnet, the checks are duplicated and performed very strictly, so that the ion species and energy of the ion beam are abnormal. Can be detected with very high reliability.

Moreover, such detection can be performed without adding a new device for performing the checking process.

According to the invention of claim 4, the same energy determinant checking step as in the invention of claim 2,
In addition to the magnetic flux density check process in the mass analysis magnet and the curvature radius check process in the energy analysis magnet, a curvature radius check process in the beam parallelizing magnet is further provided, and energy analysis is performed by the curvature radius check process in this beam paralleling magnet. Similar to the step of checking the radius of curvature in the magnet, also in the portion of the beam collimating magnet, it is possible to detect anomalies in the ion species and energy of the ion beam before and during the implantation.

A radius-of-curvature checking step in such a beam collimating magnet, an energy-determining factor checking step, a magnetic flux density checking step in a mass analysis magnet, and a radius-of-curvature checking step in an energy-analysis magnet, which are similar to those in the invention of claim 2. As a result, since the checks are performed in a number of layers and extremely strictly performed, it is possible to detect abnormalities of ion species and energy of the ion beam with extremely high reliability.

Moreover, such detection can be performed without adding a new device for performing the checking process.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of an ion implantation apparatus to which the present invention is applied.

[Explanation of symbols]

 2 ion source 8 ion beam 10 extraction power supply 12 mass analysis magnet 14 acceleration tube 20 acceleration power supply 22 deceleration mode power supply 24 energy analysis magnet 26 scanning magnet 28 beam collimating magnet 32 target 34 scanning mechanism

Claims (4)

[Claims] 1. An ion source for extracting an ion beam, and an ion source provided downstream of the ion source for extracting and extracting ions having a specific mass number and valence number from the ion beam extracted from the ion source. A mass analysis magnet, an acceleration tube provided downstream of the mass analysis magnet for accelerating or decelerating the ion beam derived from the mass analysis magnet, and an acceleration tube provided downstream of the acceleration tube. A method in an ion implantation apparatus having an energy analysis magnet for selecting and deriving ions of specific energy from an ion beam derived from an acceleration tube, and injecting the ion beam derived from this energy analysis magnet into a target. In the energy analysis magnet before and during implantation into the target. Calculate the radius of curvature of the ion beam in the energy analysis magnet based on the value at the time of checking the magnetic flux density, the mass number of ions, the valence and the total applied voltage to the ion beam at that time. An ion implantation condition abnormality detection method for an ion implanter, comprising: a step of checking a radius of curvature in an energy analysis magnet, which checks whether or not the radius is within a predetermined allowable range with respect to the reference value. 2. An ion source for extracting an ion beam, and an ion source provided downstream of the ion source for extracting and extracting ions of a specific mass number and valence number from the ion beam extracted from the ion source. A mass analysis magnet, an acceleration tube provided downstream of the mass analysis magnet for accelerating or decelerating the ion beam derived from the mass analysis magnet, and an acceleration tube provided downstream of the acceleration tube. A method in an ion implantation apparatus having an energy analysis magnet for selecting and deriving ions of specific energy from an ion beam derived from an acceleration tube, and injecting the ion beam derived from this energy analysis magnet into a target. The value at the time of checking the extraction voltage applied to the ion source to extract the ion beam. And a value at the time of checking the acceleration voltage applied to the acceleration tube for ion beam acceleration or the deceleration mode voltage applied for ion beam deceleration between the ion source and the acceleration tube, An energy determinant checking step of checking whether or not it is within a predetermined allowable range with respect to the set value before and during implantation into the target, and for each set value of the extraction voltage, the mass number and the value of the ion at the time of checking The magnetic flux density check process in the mass analysis magnet to check whether the value at the time of checking the magnetic flux density in the mass analysis magnet against the number is within the predetermined allowable range for the reference value before and during the injection into the target. And the flux density check in the energy analysis magnet before and during implantation into the target. And the value at the time of click,
Calculate the radius of curvature of the ion beam in the energy analysis magnet based on the mass number of ions, the valence, and the total applied voltage to the ion beam, and the radius of curvature is within a predetermined allowable range with respect to the reference value. And a step of checking a radius of curvature in the energy analysis magnet for checking whether or not the condition is present in the ion implantation apparatus. 3. An ion source for extracting an ion beam, and an ion source provided downstream of the ion source for selecting and extracting ions having a specific mass number and valence from the ion beam extracted from the ion source. A mass analysis magnet, an acceleration tube provided downstream of the mass analysis magnet for accelerating or decelerating the ion beam derived from the mass analysis magnet, and an acceleration tube provided downstream of the acceleration tube. An energy analysis magnet that selects and derives ions of specific energy from the ion beam derived from the acceleration tube, and an ion beam derived from the energy analysis magnet that is provided on the downstream side of the energy analysis magnet. The scanning magnet that performs one-dimensional scanning and the scanning magnet that is provided on the downstream side of the scanning magnet. A beam collimating magnet that bends the ion beam derived from the net so that it is parallel to the reference axis, and an ion beam that is provided downstream of this beam collimating magnet and is derived from the beam collimating magnet A scanning mechanism that mechanically scans the target in the irradiation region of the target in a direction substantially orthogonal to the scanning direction of the ion beam in the scanning magnet before and during implantation into the target. The first curvature of the ion beam in the energy analysis magnet is based on the value at the time of checking the magnetic flux density in the energy analysis magnet, the mass number of ions at that time, the valence, and the total applied voltage to the ion beam. The radius is calculated, and the first radius of curvature is a predetermined value with respect to the reference value. The value at the time of checking the radius of curvature in the energy analysis magnet for checking whether it is within the allowable range, the magnetic flux density in the beam collimating magnet before and during the implantation into the target, and the ion at that time A second radius of curvature of the ion beam in the beam collimating magnet is calculated based on the mass number, the valence, and the total applied voltage to the ion beam, and the second radius of curvature and the first radius of curvature are calculated. And a radius-of-curvature checking step in the beam collimating magnet for checking whether or not the ratio is within a predetermined allowable range with respect to the reference value. Anomaly detection method. 4. An ion source for extracting an ion beam, and an ion source provided downstream of the ion source for selecting and extracting ions having a specific mass number and valence number from the ion beam extracted from the ion source. A mass analysis magnet, an acceleration tube provided downstream of the mass analysis magnet for accelerating or decelerating the ion beam derived from the mass analysis magnet, and an acceleration tube provided downstream of the acceleration tube. An energy analysis magnet that selects and derives ions of specific energy from the ion beam derived from the acceleration tube, and an ion beam derived from the energy analysis magnet that is provided on the downstream side of the energy analysis magnet. The scanning magnet that performs one-dimensional scanning and the scanning magnet that is provided on the downstream side of the scanning magnet. A beam collimating magnet that bends the ion beam derived from the net so that it is parallel to the reference axis, and an ion beam that is provided downstream of this beam collimating magnet and is derived from the beam collimating magnet A scanning mechanism for mechanically scanning a target in the irradiation region of the scanning magnet in a direction substantially orthogonal to the scanning direction of the ion beam in the scanning magnet, wherein the ion beam is extracted to the ion source. Value at the time of checking the extraction voltage applied for the purpose of acceleration, and the acceleration voltage applied to the acceleration tube for ion beam acceleration or applied for deceleration of the ion beam between the ion source and the acceleration tube. Check whether the value of deceleration mode voltage at the time of checking is within the predetermined allowable range for each set value. For the energy determinant checking step to check before and during implantation, for each set value of the extraction voltage, the value at the time of checking the magnetic flux density in the mass analysis magnet with respect to the mass number and valence of the ions at the time of the check, A magnetic flux density checking step in a mass analysis magnet for checking whether it is within a predetermined allowable range with respect to a reference value before and during injection into a target, and in the energy analysis magnet before and during injection into a target. The first radius of curvature of the ion beam in the energy analysis magnet is calculated based on the value at the time of checking the magnetic flux density, the mass number of ions, the valence, and the total applied voltage to the ion beam at that time, and The first radius of curvature is within the predetermined tolerance range for the reference value. Whether or not the radius of curvature is checked in the energy analysis magnet, and the magnetic flux density is checked in the beam parallelizing magnet before and during implantation into the target, the mass number of ions at that time, and the valence. The second radius of curvature of the ion beam in the beam collimating magnet is calculated based on the number and the total applied voltage to the ion beam, and the ratio between the second radius of curvature and the first radius of curvature is calculated. And a radius-of-curvature checking step in the beam collimating magnet for checking whether or not this ratio is within a predetermined allowable range with respect to the reference value.