JP3358336B2 - Method for detecting abnormal implantation conditions in ion implantation system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implantation apparatus for irradiating a target with an ion beam to perform ion implantation.

[0002]

2. Description of the Related Art FIG. 1 is a schematic diagram showing an example of an ion implantation apparatus to which the present invention is applied. This apparatus magnetically scans the ion beam 8 in parallel and simultaneously sets the target 3
2 is a so-called hybrid parallel scan type ion implantation apparatus that mechanically scans the ion implantation apparatus 2.

[0003] This ion implantation apparatus is provided with an ion source 2 for extracting an ion beam 8 and a specific ion species (specified ion source) provided on the downstream side of the ion source 2 from the ion beam 8 extracted from the ion source 2. The ion species is specified by a mass number and a valence number), and a mass analysis magnet 12 is provided downstream of the mass analysis magnet 12, and the ions are provided from the mass analysis magnet 12. Acceleration tube 14 for accelerating or decelerating beam 8
And an energy analysis magnet 24 provided downstream of the acceleration tube 14 to select and derive ions of a specific energy from the ion beam 8 derived from the acceleration tube 14. The energy analysis magnet 24 provided on the downstream side
Scanning magnet 26 that magnetically scans the ion beam 8 derived from the magnetic field one-dimensionally (along the paper surface in the illustrated example).
Provided on the downstream side of the scanning magnet 26, the ion beam 8 derived from the scanning magnet 26 is bent back so as to be parallel to the reference axis 30, and the ion beam 8 cooperates with the scanning magnet 26. A beam collimating magnet 28 for performing parallel scanning of the beam 8, and a target (for example, a target (e.g., a target) within the irradiation area of the ion beam 8 provided downstream of the beam collimating magnet 28 and derived from the beam collimating magnet 28. A scanning mechanism 34 for mechanically scanning the wafer (wafer) 32 in a direction substantially orthogonal to the scanning direction of the ion beam 8 by the scanning magnet 26 (in the illustrated example, in the direction of the front and back of the paper). The target 32 is irradiated with the ion beam 8 to perform ion implantation.

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

[0005] The accelerating tube 14 has a multi-stage electrode 16, and an accelerating voltage _VA is applied to both ends of the accelerating tube 20 from a DC accelerating power supply 20 with its upstream side being a positive side in the case of an accelerating mode. You. The most downstream electrode 16 is grounded. In the case of the deceleration mode, the acceleration power supply 20 is cut off, and the direct current deceleration mode is set between the plasma generation unit 4 of the ion source 2 and the ground with the former being the positive side, as shown by the two-dot chain 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 vessel 46, a reversible motor 38 mounted on a rotating shaft 37, and a rotating shaft (not shown). , A motor 42 attached to a tip of the arm 40, and a holder 44 attached to a rotating shaft (not shown) 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 the arrow 61 by the motor 36. By rotating the arm 40 as shown by the arrow 62 by the motor 38, the target 32 can be mechanically scanned in the front and back directions on the paper surface. By rotating the holder 44 as shown by an arrow 63 by the motor 42, the target 32 can be rotated during the injection.

The ion implantation apparatus further includes a control device 50 for controlling the entire ion implantation device, and a man-machine controller 52 connected to the control device 50 and performing input / output with an operator. . The man-machine controller 52 has a display device 54.

With the above configuration, the target 32 is irradiated with the ion beam 8 having a desired ion species and energy while scanning in parallel, and the target 32 is mechanically scanned to uniformly implant ions over the entire surface of the target 32. be able to.

The magnetic scanning of the ion beam 8 using the scanning magnet 26 and the beam collimating magnet 28 is performed by a voltage applied to the scanning electrode as in the case of electrostatic scanning. This is because it is possible to prevent the electron beam in the ion beam 8 from being robbed and the space charge of the ion to be increased to prevent the ion beam from diverging. This is particularly effective when a large amount of the ion beam 8 is treated with low energy. Is remarkable.

The parallel scanning of the ion beam 8 with the provision of the beam collimating magnet 28 is performed by the target 32.
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 the substrate.

[0011]

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

An erroneous injection in which such injection conditions are erroneously performed must be avoided. In particular, in a production machine that processes a large number of targets 32, if erroneous injection occurs, serious damage will occur. Therefore, thorough care must be taken to prevent erroneous injection.

[0013] Of the above 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 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 desired ones.

That is, with respect to the energy of the ion beam 8, conventionally, the extraction voltage V _E , the acceleration voltage _VA and the deceleration mode voltage V _D which determine the energy are converted into a voltage comprising a voltage measuring resistor and a D / A converter. Each was measured by a measurement system. Among them, especially for the accelerating voltage V _A , two voltage measurement systems were provided independently of each other, and it was checked by software that the difference between the measured data was within a certain width. It was not carried out any check for 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 measurement systems are provided as in the case of the acceleration voltage _VA , if the two systems are shifted in the same manner, it cannot be found.

Meanwhile, for the ionic species, conventionally, for example as shown in Table 1, for each extraction voltage V _E, the mass number of the ion, a combination of magnetic flux density at valence and mass analyzing magnet 12 of the ion, 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 corresponding value in the mass table ( That is, it was checked whether the magnetic flux density was within the allowable range (at the corresponding extraction voltage V _E , mass number and valence).

[0018]

[Table 1]

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

Accordingly, it is a main object of the present invention to provide a method for detecting an abnormal condition of an implantation condition capable of correctly detecting an abnormality of an ion species and energy of an ion beam.

[0021]

In order to achieve the above object, a first method for detecting an abnormality in injection conditions according to the present invention is to provide a method for detecting a magnetic flux density in the energy analysis magnet before and during injection into a target. And the radius of curvature of the ion beam in the energy analysis magnet is calculated based on the mass number and valence of the ions at that time and the total applied voltage to the ion beam, and the radius of curvature is a predetermined tolerance with respect to the reference value. A step of checking a radius of curvature of the energy analysis magnet for checking whether or not the radius is within the range is provided.

According to a second method of detecting abnormal implantation conditions of the present invention, a check value of an extraction voltage applied to the ion source for extracting an ion beam and a voltage applied to the acceleration tube for accelerating the ion beam are applied. Whether 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 acceleration tube is within a predetermined allowable range for each set value. An energy determining factor check 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 spectrometer for the mass number and valence of ions at the time of checking Mass spectrometer to check before and during injection to a target to see if it is within a predetermined tolerance for its reference value. Checking the magnetic flux density in the net, before and during implantation into the target, the value at the time of checking the magnetic flux density in the energy analysis magnet, and the mass number, valence, and total applied voltage of the ion beam at that time. Calculating a radius of curvature of the ion beam in the energy analysis magnet based on the calculated radius of curvature, and checking whether the radius of curvature is within a predetermined allowable range with respect to the reference value. It is characterized by having.

According to a third method of detecting an abnormal condition of implantation of the present invention, the value at the time of checking the magnetic flux density in the energy analysis magnet, and the mass number, valence and ion number of the ion before and during the implantation into the target. Calculating a first radius of curvature of the ion beam in the energy analysis magnet based on the total applied voltage to the beam; and determining whether the first radius of curvature is within a predetermined allowable range with respect to the reference value. Checking the radius of curvature check step in the energy analysis magnet, before and during implantation into the target, the value at the time of checking the magnetic flux density in the beam collimating magnet,
The second radius of curvature of the ion beam in the beam collimating magnet is calculated based on the mass number and valence of the ions at that time and the total applied voltage to the ion beam, and the second radius of curvature and the second radius of curvature are calculated. A step of checking the radius of curvature of the beam collimating magnet to determine whether the ratio with the radius of curvature is within a predetermined allowable range with respect to the reference value.

According to a fourth method of detecting an abnormal condition of implantation of the present invention, a check value of an extraction voltage applied to the ion source for extracting an ion beam and a voltage applied to the acceleration tube for accelerating the ion beam are applied. Whether 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 acceleration tube is within a predetermined allowable range for each set value. An energy determining factor check 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 spectrometer for the mass number and valence of ions at the time of checking Mass spectrometer to check before and during injection to a target to see if it is within a predetermined tolerance for its reference value. Checking the magnetic flux density in the net, before and during implantation into the target, the value at the time of checking the magnetic flux density in the energy analysis magnet, and the mass number, valence, and total applied voltage of the ion beam at that time. Calculating a first radius of curvature of the ion beam in the energy analysis magnet based on the calculated value, and checking whether the first radius of curvature is within a predetermined allowable range with respect to the reference value. Radius of curvature check step, before and during implantation into the target, based on the value at the time of checking the magnetic flux density in the beam collimating magnet, and the mass number, valence and the total applied voltage to the ion beam at that time. The second tune 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 curvature radius checking step.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The most strict embodiment of the method for detecting an abnormal condition of implantation in the ion implantation apparatus shown in FIG.

The injection condition abnormality detecting method of this embodiment
An energy determining factor check step, a magnetic flux density check step for a mass analysis magnet, a curvature radius check step for an energy analysis magnet, and a curvature radius check step for a beam parallelizing magnet are provided. Processing such as data registration, calculation, comparison, and the like in these check steps is performed in, for example, the control device 50 and the man-machine controller 52. Hereinafter, each of these steps will be described in detail.

(1) Energy determinant checking step

In this checking step, the extraction voltage V _E
The acceleration the current value of the voltage V _A (if the acceleration mode), or (if the deceleration mode) each current value of the extraction voltage V _E deceleration mode voltage V _D is, within a predetermined tolerance for each set value Check whether or not there is. The current value is the current value at the time of the check (the same applies hereinafter).

As described above, the extraction voltage V _E is applied to the ion source 2, more specifically, between the plasma generator 4 and the extraction electrode 6 from the extraction power source 10 for extracting the ion beam 8. Voltage. Acceleration voltage V _A
Is the voltage applied from the acceleration power supply 20 to both ends of the acceleration tube 14 to accelerate the ion beam 8 in the acceleration mode, as described above (as shown in FIG. 1). In the acceleration mode, the total applied voltage to the ion beam 8 is _VE + _VA , and the energy of the ion beam 8 is determined by this. As described above (as indicated by the two-dot chain line in FIG. 1), the deceleration mode voltage V _D is set at the ion source 2 during the deceleration mode.
Is 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 becomes V _D , and the energy of the ion beam 8 is determined by this.

Specifically, each of the voltages V _E , V _A and V _D
, The tolerance for each set value is ±
alpha ₁ kV, may be set as ± alpha ₂ kV and ± α ₃ kV, normal if it is within the allowable current value is a predetermined time or more ranges of the respective voltages V _E, V _A and V _D, and no if abnormal . The reason for requiring a certain time or longer is to ignore instantaneous value fluctuations and the like (the same applies to the following). However, deceleration mode, the extraction voltage V _E is, because it does not relate to the energy of the ion beam 8, may not be performed 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-described check is performed immediately before the start of injection, and if abnormal, "injection is disabled" and an error message is displayed on the display device 54 of the man-machine controller 52. If normal, the process proceeds to the injection process. "Implantation impossible" means that the control sequence for ion implantation does not proceed any more in the control device 50 (the same applies hereinafter).

Further, the above-described check is performed during the injection, and if an abnormality is detected, the state is set to “hold” and an error message is displayed on the display device 54. If normal, the injection process is continued. "Hold" refers to extracting the ion beam 8 from the ion source 2 but diverting it to a position not incident on the target 32, and stopping the mechanical scanning of the target 32 (the same applies hereinafter).

By performing the above check, it is possible to detect the abnormalities of the voltages V _E , _VA and V _{D which} cause the energy abnormality of the ion beam 8 before and during the implantation. As a result, an abnormality in the energy of the ion beam 8 can be detected.

Further, when the check result is abnormal, the above-described processing of “implantation impossible” and “hold” is performed, so that the target 32 is immediately before injection and immediately during injection. On the other hand, abnormal injection with incorrect energy can be prevented.

(2) Step of Checking Magnetic Flux Density in Mass Spectrometer Magnet

[0037] In this checking step, for each set value of the extraction voltage V _E, the current value of the magnetic flux density of the mass analyzing magnet 12 with respect to the mass number and valence of ions during checking, the predetermined allowable range for the reference value Is checked using mass table data. The current value of the magnetic flux density in the mass analysis magnet 12 is determined using, for example, a hole probe (not shown) conventionally embedded in the mass analysis magnet 12.

As shown in Table 2, the mass table data shows, for each extraction voltage V _E , the mass number of ions, the valence 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]

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

With respect to the total magnetic flux density 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 expression holds.

[0042]

## EQU1 ## where _{B l ≦ B s ≦ B u} , B s is the magnetic flux density, B _u is the allowable upper limit, B _l
Is its lower limit.

A 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 represented by the following equation.

[0044]

R = (1 / B) √ (2 mV / q) where B is the magnetic flux density [T] and m is the mass number of the ion [k
g] and q are the charge amount of the ion [C], and V is the ion beam 8
Is the total applied voltage [V]. Further, the mass number of the ion M, when the mass m _p of the proton, is m = Mm _p. Further, assuming that the ion valence is n and the elementary charge is e, q = n
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 n, the following equation is obtained.

[0046]

R = 45.66 (1 / B ₁ ) √ (MV ₁ / n)

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

The above-described check of the mass table validity is performed when mass table data is set and registered. If any one of the data is abnormal, the 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 performing such a mass table validity check, it is possible to prevent abnormal data from being registered in the mass table beforehand. The reliability of checking the magnetic flux density is further improved.

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 performed immediately before the start of injection,
In the case of an abnormality, “injection impossible” is set and the display device 54
Displays an error message at If normal, the process proceeds to the injection process. In addition, the above checks were performed during the injection,
In the case of an abnormality, “hold” is set and the display device 54
Displays an error message at If normal, the injection process is continued.

By checking the magnetic flux density in the mass analysis magnet 12 as described above, the conditions for deriving the ion beam 8 of the correct ion type, that is, the correct mass number and valence from the mass analysis magnet 12 are satisfied. Since it can be detected before and during the implantation, the abnormality of the ion species can be detected.

When the check result is abnormal, by performing the above-mentioned "implantation impossible" and "hold" processing, the target 32 can be promptly set before the injection and immediately during the injection. On the other hand, it is possible to prevent abnormal implantation with incorrect ion species.

(3) Step of checking radius of curvature in energy analysis magnet

In this checking step, the ion beam in the energy analysis magnet 24 is determined 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 voltage applied to the ion beam 8. calculating a curvature radius R _F of 8, and the radius of curvature is checked whether 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 hole probe (not shown) conventionally embedded in the energy analysis magnet 24. Total applied voltage to the ion beam 8, as described above, when the acceleration mode is the sum of the accelerating voltage V _A and the extraction voltage V _E (i.e. V _E + V _A),
For deceleration mode is the deceleration mode voltage V _D.

Specifically, the ion implantation apparatus is adjusted to a preferable state, and the mass number and valence of the ions, the total applied voltage to the ion beam 8 and the measured values of the magnetic flux density at the energy analysis magnet 24 at that time are adjusted. One set is collected and registered as data. Table 3 shows an example. Then, this data is substituted into M, n, V ₁ and B ₁ in the above equation (3) to determine a radius of curvature R at that time, and this is set as a reference value R _{0 of the} radius of curvature in the energy analysis magnet.
By the way, the data as shown in the above equation (3) is, for example,
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 the check, the mass number and valence of the ions at that time, and the total applied voltage to the ion beam 8, the radius of curvature R _{F is obtained} from the above equation (3). And compares it with the reference value R ₀ . Specifically, it is checked whether or not the radius of curvature R _F falls within an allowable range of ± x ₂ % with respect to the reference value R ₀ . By the way, this x ₂ is, for example, is set to man-machine controller 52.

Prior to such a check, in this embodiment, in order to confirm the validity of the registered data itself as shown in Table 3 above, the reference value R _{0 of the} radius of curvature of the energy analysis magnet 24 obtained from the data is obtained. However, it is checked whether or not the value falls within a range of ± x ₂ % based on the original design value. This confirmation is performed when the data is registered. In the case of an 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 registered data, it is possible to prevent abnormal data from being registered. Therefore, the radius of curvature of the energy analysis magnet 24 can be checked using the registered data. Reliability is further improved.

The check of the radius of curvature R _F is performed both before and during the implantation of the target 32. That is, the above-described check is performed immediately before the start of injection, and if abnormal, “injection impossible” is set, and an error message is displayed on the display device 54. If normal, the process proceeds to the injection process. Further, the above-described check is performed during the injection, and if an abnormality is detected, the state is set to “hold” and an error message is displayed on the display device 54. If normal, the injection process is continued.

As can be seen from Equation 3, information on the mass number and valence of ions (ie, ion species) and the total applied voltage to the ion beam 8 (ie, energy of the ion beam 8) is known from the above-mentioned radius of curvature R _F. By performing the above-described check, abnormalities in the ion species and energy of the ion beam 8 can be correctly detected before and during implantation.

When the check result is abnormal, by performing the above-described processing of “implantation impossible” and “hold”, the target 32 is immediately before injection and immediately during injection. On the other hand, it is possible to prevent abnormal implantation with erroneous ion species or energy.

(4) Step of checking radius of curvature in 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 used. or ion beam 8 to calculate the radius of curvature R _C of, and determine the ratio of the curvature radius R _F in the with the radius of curvature R _C energy analyzing magnet 24, this ratio is 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.

More specifically, the beam collimating magnet 28
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 and the total application to the ion beam 8 at that time are measured. Based on the voltage, the radius of curvature R _C is obtained from the above equation (3), and the ratio R _C / R _F between the radius of curvature R _C and the radius of curvature R _F of the energy analysis magnet 24 is obtained. Check whether is within the allowable range of ± x _3% of. The value of the reference value K is, for example, a ratio of the design values of both the radii of curvature R _F and R _C. Incidentally The K and the x _3, for example is set to man-machine controller 52.

The check of the radius of curvature R _C is performed both before and during the implantation of the target 32. That is, the above-described check is performed immediately before the start of injection, and if abnormal, “injection impossible” is set, and an error message is displayed on the display device 54. If normal, the injection process is shifted to the process. Further, the above-described check is performed during the injection, and if an abnormality is detected, the state is set to “hold” and an error message is displayed on the display device 54. If normal, the injection process is continued.

Similarly to the case of the radius of curvature R _F , as can be seen from the equation (3), the mass number and valence (that is, ion species) of the ions and the total applied voltage to the ion beam 8 are also the same as the radius of curvature R _C. Since the information of the ion beam 8 is included in the beam collimating magnet 28, abnormalities in the ion species and energy of the ion beam 8 can be injected into the beam collimating magnet 28. It can be detected correctly before and during the injection.

When the check result is abnormal, by performing the above-described processing of “implantation impossible” and “hold”, the target 32 can be immediately before injection and immediately during injection. On the other hand, it is possible to prevent abnormal implantation with erroneous ion species or energy.

Since each of the above checks is a check of the validity of software, unlike a conventional case where two voltage measurement systems are used, a new check for performing a check process is performed. There is also an advantage that no additional equipment (hardware) needs to be added.

It should be noted that the more the above-described steps of the energy determining factor check step, the magnetic flux density check step of the mass analysis magnet, the curvature radius check step of the energy analysis magnet, and the curvature radius check step of the beam collimating magnet, the more the more steps are performed. Although it is more preferable because the checks become multiple and the checks become strict, it is more preferable to simply execute the radius of curvature check step in the energy analysis magnet, because of the above-described reasons, the abnormality of the ion species and energy of the ion beam 8 can be reduced. It can be detected correctly before and during injection.

The configuration downstream of the energy analysis magnet 24 of the ion implantation apparatus is not limited to the example shown in FIG. For example, a simple hybrid scan type ion implanter which does not scan the ion beam 8 in parallel without providing the beam collimating magnet 28 may be used, or the ion beam 8 may be used in which the scanning magnet 26 and the beam collimating magnet 28 are not provided. Instead of scanning, a mechanical scan type ion implantation apparatus may be used in which the target 32 is mounted on a rotating and translating wafer disk and scanned mechanically. In these cases, since the beam collimating magnet 28 does not exist, the above-described fourth checking step, that is, the step of checking the radius of curvature of 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 of ions (ie, ion species) and the total applied voltage to the ion beam (ie, energy of the ion beam). , The abnormality of the ion species and energy of the ion beam can be correctly detected before and during the implantation.

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

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

Before and after the injection, it is confirmed that the condition for deriving the ion beam of the correct ion species from the mass analysis magnet, that is, the ion beam having the correct mass number and valence, is not satisfied by the magnetic flux density check step in the mass analysis magnet. Since it can be detected inside, it is possible to detect an abnormality of the ion species.

Further, in the radius of curvature checking step in the energy analysis magnet, the radius of curvature in the energy analysis magnet includes the mass number and valence of ions (ie, ion species) and the total applied voltage to the ion beam (ie, energy of the ion beam). , The abnormality of the ion species and energy of the ion beam can be detected before and during the implantation.

In the step of checking the energy determinant, the step of checking the radius of curvature of the mass analysis magnet, and the step of checking the radius of curvature of the energy analysis magnet, the checks are performed in a multiplex manner and very strictly. Abnormalities in ion species and energy can be detected with very high reliability.

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

According to the third aspect of the present invention, the radius of curvature of the energy analysis magnet includes the mass number and valence (ie, ion species) of the ion and the total applied voltage to the ion beam in the radius of curvature check step in the energy analysis magnet. Since the information of (i.e., the energy of the ion beam) is included, abnormalities in the ion species and energy of the ion beam can be detected before and during the implantation.

Also, in the radius of curvature checking step in the beam collimating magnet, as in the case of the radius of curvature checking step in the energy analysis magnet, abnormalities in the ion species and energy of the ion beam are injected into the beam collimating magnet as well. It can be detected before and during the injection.

In the step of checking the radius of curvature in the energy analysis magnet and the step of checking the radius of curvature in the beam collimating magnet, the check is performed in duplicate and very strictly, so that the ion species and energy of the ion beam are abnormal. Can be detected with very high reliability.

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

According to the fourth aspect of the present invention, the same energy determining factor checking step as in the second aspect of the present invention,
In addition to the magnetic flux density check step in the mass analysis magnet and the radius of curvature check step in the energy analysis magnet, the method further includes a radius of curvature check step in the beam collimation magnet. As in the case of the radius of curvature check step for the magnet, an abnormality in the ion species and energy of the ion beam can be detected before and during the implantation also in the beam collimating magnet.

The step of checking the radius of curvature in such a beam collimating magnet, the step of checking the energy determining factor, the step of checking the magnetic flux density in the mass analysis magnet, and the step of checking the radius of curvature in the energy analysis magnet are the same as in the second aspect of the present invention. As a result, the checks are performed in multiple layers and extremely strictly performed, so that abnormalities in the ion species and energy of the ion beam can be detected with extremely high reliability.

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

[Brief description of the 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 Accelerator 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

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-225944 (JP, A) JP-A-63-96852 (JP, A) JP-A-62-295347 (JP, A) JP-A-6-295347 342639 (JP, A) JP-A 1-152445 (JP, U) JP-A 7-3131 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 37/317 H01J 37 / 05 C23C 14/48 H01L 21/265

Claims (4)

(57) [Claims] 1. An ion source for extracting an ion beam, and an ion source provided downstream of the ion source for selectively 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 an 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 a specific energy from an ion beam derived from the accelerator tube; and a method in an ion implantation apparatus configured to cause the ion beam derived from the energy analysis magnet to be incident on a target. Before and during implantation on the target, The 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 and the mass number, valence, and total applied voltage of the ion beam at that time, and the radius of curvature is calculated. A method for detecting an abnormality of an implantation condition in an ion implantation apparatus, comprising: a step of checking a radius of curvature of an energy analysis magnet for checking whether or not a reference value is within a predetermined allowable range. 2. An ion source for extracting an ion beam, and an ion source provided on the downstream side of the ion source for selecting and deriving ions of 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 an 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 a specific energy from an ion beam derived from the accelerator tube; and a method in an ion implantation apparatus configured to cause the ion beam derived from the energy analysis magnet to be incident on a target. And a check value of an extraction voltage applied to the ion source for extracting an ion beam. And an acceleration voltage applied to the acceleration tube for accelerating the ion beam or a value at the time of checking the deceleration mode voltage applied for decelerating the ion beam between the ion source and the acceleration tube. An energy determinant checking step for checking whether or not the set value is within a predetermined allowable range before and during the implantation with respect to the target; and for each set value of the extraction voltage, a mass number and a value of ions at the time of the check. A magnetic flux density check step in the mass analysis magnet, which checks whether the value of the magnetic flux density in the mass analysis magnet with respect to the number is within a predetermined allowable range with respect to the reference value before and during injection into the target. Before and during injection into the target, the magnetic flux density in the energy analysis magnet is checked. And the value at the time of click,
The radius of curvature of the ion beam in the energy analysis magnet is calculated based on the mass number and valence of the ion at that time 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. A step of checking a radius of curvature of the energy analysis magnet for checking whether or not the condition exists in the ion analysis apparatus. 3. An ion source for extracting an ion beam, and an ion source provided downstream of the ion source for selecting and deriving ions of 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 an 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 a specific energy from an ion beam derived from the accelerator tube, and a magnet provided on the downstream side of the energy analysis magnet, for ionizing the ion beam derived from the energy analysis magnet. Scanning magnet for scanning one dimensionally and a scanning magnet provided downstream of the scanning magnet. A beam collimating magnet that bends the ion beam derived from the net so as to be parallel to the reference axis, and an ion beam that is provided downstream of the beam collimating magnet and is derived from the beam collimating magnet A scanning mechanism that mechanically scans the target in a direction substantially orthogonal to the scanning direction of the ion beam in the scanning magnet in the irradiation region of the ion implantation apparatus, before and during implantation with respect to the target. First, the first curvature of the ion beam in the energy analysis magnet is determined based on the value at the time of checking the magnetic flux density in the energy analysis magnet, the mass number and valence of the ions at that time, and the total applied voltage to the ion beam. Calculating a radius, and determining that the first radius of curvature is a predetermined radius with respect to the reference value. A radius of curvature check step in the energy analysis magnet, and a value at the time of checking the magnetic flux density in the beam collimating magnet before and during implantation with respect to the target, 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. A step of checking the radius of curvature of the beam collimating magnet to check whether 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 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 an 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 a specific energy from the ion beam derived from the accelerator tube, and a magnetic ion beam that is provided downstream of the energy analysis magnet and is derived from the energy analysis magnet. Scanning magnet for scanning one dimensionally and a scanning magnet provided downstream of the scanning magnet. A beam collimating magnet that bends the ion beam derived from the net so as to be parallel to the reference axis, and an ion beam that is provided downstream of the beam collimating magnet and is derived from the beam collimating magnet A scanning mechanism for mechanically scanning the target in a direction substantially perpendicular to the scanning direction of the ion beam in the scanning magnet in the irradiation area of the ion implantation apparatus, wherein the ion source is extracted by the ion source. The value at the time of check of the extraction voltage applied for the acceleration and the acceleration voltage applied to the acceleration tube for accelerating the ion beam or the acceleration voltage applied between the ion source and the acceleration tube for deceleration of the ion beam Check whether the value at the time of checking the deceleration mode voltage is within a predetermined allowable range for each set value. The energy determinant checking step to check before and during implantation, and for each set value of the extraction voltage, the value at the time of checking the magnetic flux density in the mass spectrometry magnet with respect to the mass number and valence of ions at the time of the check, A magnetic flux density check step in the mass spectrometer magnet before and during the injection to the target to check whether it is within a predetermined tolerance with respect to the reference value, and before and during the injection to the 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, and the mass number, valence and the total applied voltage of the ion beam at that time, and The first radius of curvature is within a predetermined allowable range with respect to the reference value; A step of checking the radius of curvature in the energy analysis magnet, and checking the value of the magnetic flux density in the beam collimating magnet before and during the implantation into the target, and the mass number and value of the ions at that time. Calculating the second radius of curvature of the ion beam in the beam collimating magnet based on the number and the total applied voltage to the ion beam, and calculating the ratio of the second radius of curvature to the first radius of curvature. A step of checking the radius of curvature of the beam collimating magnet to determine whether the ratio is within a predetermined allowable range with respect to the reference value.