Ion implantation method and ion implantation apparatus

Abstract

The invention relates to an ion implantation method and an ion implantation device. By means of the ion implantation method and the ion implantation device, secondary electrons formed by an electron gun and plasma move towards the ion beam, the secondary electrons can be neutralized with positive charges on the surface of the ion beam, and when the emission current is formed, on the basis of the ion beam current and the emission parameters of the electron gun, the emission current is generated. And the gas flow forming the plasma is adjusted by using the corresponding relational expression IEC = ax < 2 > + bx + c to obtain the corresponding emission current, so that the stable emission current can be obtained, positive charges on the surface of an ion beam can be conveniently neutralized by using the emission current, and the risk of arc discharge damage caused by ion implantation is reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to an ion implantation method and an ion implantation device. Background Art

[0002] In the semiconductor manufacturing process, the corresponding type of impurity ions are doped into the substrate by using the ion implantation process. The ion beam incident on the substrate usually has a positive charge, which will cause the charge accumulation on the substrate surface during ion implantation. However, with the development of process technology, the gate dielectric layer formed on the substrate surface is getting thinner and thinner, and the critical dimensions of the device are getting smaller and smaller. The positive charge accumulated on the substrate surface due to ion implantation is prone to cause arcing damage (Arcing Defect), which is increasingly becoming a key factor restricting the performance, yield and reliability of semiconductor devices.

[0003] In order to reduce the accumulation of positive charges in the ion beam on the substrate surface, some ion implantation equipment is equipped with an electron generation module, the principle of which is to use an electron gun to generate electrons and make the electrons collide with plasma to generate secondary electrons, which move toward the ion beam under the attraction of the positive charges in the ion beam and neutralize the positive charges on the surface of the ion beam. The movement of the secondary electrons will form an emission current.

[0004] However, research has found that even if the parameters for generating the secondary electrons are set the same, the emission current will change in actual work, resulting in unstable neutralization effect on the positive charge on the surface of the ion beam, which is not conducive to reducing the risk of arc discharge damage caused by ion implantation. Summary of the invention

[0005] Research has found that in addition to being related to the parameter settings for generating the secondary electrons, the emission current is also affected by the ion beam current. As a result, even if the parameter settings for generating the secondary electrons are the same, the emission current will also change when the ion beam current is different, affecting the neutralization effect of the positive charge on the surface of the ion beam, which is not conducive to reducing the risk of arc discharge damage caused by ion injection.

[0006] In order to form a stable emission current to effectively neutralize the positive charge on the surface of the ion beam and reduce the risk of arc discharge damage caused by ion implantation, the present invention provides an ion implantation method and an ion implantation device.

[0007] In one aspect, the present invention provides an ion implantation method, comprising:

[0008] forming an ion beam for ion implantation according to an ion implantation requirement, wherein the ion beam has a positive charge and corresponds to an ion beam current;

[0009] Using an electron gun to emit electrons and generate plasma, the electrons emitted by the electron gun collide with the plasma to form secondary electrons, the secondary electrons move toward the ion beam under the attraction of positive charges in the ion beam to form an emission current, and the secondary electrons neutralize the positive charges on the surface of the ion beam;

[0010] Wherein, when forming the emission current, based on the ion beam current and the emission parameters of the electron gun, the corresponding relation I is used. EC =ax 2 +bx+c adjusts the gas flow rate of forming the plasma to obtain the corresponding emission current, I EC represents the emission current, x represents the gas flow rate, and a, b and c are fitting coefficients.

[0011] Optionally, the electron gun is a filament electron gun, and the emission parameters of the electron gun include the arc starting current of the filament electron gun.

[0012] Optionally, when forming the emission current, based on the ion beam current and the gas flow rate for forming the plasma, the corresponding relationship I is used. EC =a′y 2 +b′y+c′y adjusts the arc starting current of the filament electron gun to obtain the corresponding emission current, I EC represents the emission current, y represents the arc starting current, and a′, b′ and c′ are fitting coefficients.

[0013] Optionally, when forming the emission current, the emission current and the current ion beam current satisfy the relationship I EC / I IC >N,I EC represents the emission current, I IC represents the ion beam current, and N is an integer greater than or equal to 1.

[0014] Optionally, before forming the ion beam and the secondary electrons, the values ​​of the ion beam current, the emission parameters of the electron gun and the gas flow rate are combined by setting multiple values ​​of the ion beam current, multiple emission parameters of the electron gun and multiple gas flow rates, and ion injection is performed separately using the obtained multiple sets of data to obtain the detection value of the emission current corresponding to each set of data. The relationship between the emission current and the gas flow rate when the ion beam current and the emission parameters of the electron gun are specified values ​​is fitted to obtain the corresponding values ​​of a, b and c.

[0015] Optionally, before forming the ion beam and the secondary electrons, without setting the ion beam, multiple emission parameters of the electron gun and multiple values ​​of the gas flow are set, the emission parameters of the electron gun and the values ​​of the gas flow are combined, and the detection value of the emission current corresponding to each set of data is obtained.

[0016] In another aspect, the present invention provides an ion implantation device, comprising:

[0017] an ion beam module, used for forming an ion beam for ion implantation according to ion implantation requirements, wherein the ion beam has a positive charge and corresponds to an ion beam current; and

[0018] An electron flow module, used for emitting electrons by using an electron gun and generating plasma, so that the electrons emitted by the electron gun collide with the plasma to form secondary electrons, and the secondary electrons move toward the ion beam under the attraction of positive charges in the ion beam to form an emission current, and the secondary electrons neutralize the positive charges on the surface of the ion beam;

[0019] Wherein, when forming the emission current, based on the ion beam current and the emission parameters of the electron gun, the corresponding relation I is used. EC =ax 2 +bx+c adjusts the gas flow rate of forming the plasma to obtain the corresponding emission current, I EC represents the emission current, x represents the gas flow rate, and a, b and c are fitting coefficients.

[0020] Optionally, the electron gun is a filament electron gun, and the emission parameters of the electron gun include the arc starting current of the filament electron gun.

[0021] Optionally, when forming the emission current, based on the ion beam current and the gas flow rate for forming the plasma, the corresponding relationship I is used. EC =a′y 2 +b′y+c′y adjusts the arc starting current of the filament electron gun to obtain the corresponding emission current, I EC represents the emission current, y represents the arc starting current, and a′, b′ and c′ are fitting coefficients.

[0022] Optionally, the ion implantation device further comprises:

[0023] A database module for storing the relational expression I related to different ion beam currents, different emission parameters of the electron gun or different gas flow rates. EC =ax 2 +bx+c and / or the relation I EC =a′y2 +b′y+c′y and the corresponding fitting coefficients.

[0024] Optionally, when forming the emission current, the emission current and the current ion beam current satisfy the relationship I EC / I IC >N,I EC represents the emission current, I IC represents the ion beam current, and N is an integer greater than or equal to 1.

[0025] By using the ion implantation method and ion implantation device provided by the present invention, secondary electrons formed by the electron gun and the plasma move toward the ion beam and can neutralize the positive charge on the surface of the ion beam. In addition, when forming the emission current, based on the ion beam current and the emission parameters of the electron gun, the corresponding relationship I is used. EC =ax 2 +bx+c adjusts the gas flow rate for forming the plasma to obtain the corresponding emission current, and can obtain a stable emission current, so as to facilitate the use of the emission current to neutralize the positive charge on the surface of the ion beam and reduce the risk of arc discharge damage caused by ion implantation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic flow chart of the ion implantation method according to an embodiment of the present invention.

[0027] Figure 2 It is a data fitting curve of the gas flow rate and emission current for forming plasma when the ion beam current and the arc starting current of the electron gun are specified values ​​in the embodiment of the present invention.

[0028] Figure 3 It is a module schematic diagram of an ion implantation device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The ion implantation method and ion implantation device of the present invention are further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer according to the following description. It should be understood that the drawings in the specification are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0030] Reference Figure 1The embodiment of the present invention relates to an ion implantation method. The ion implantation method can be used to implant ions into a semiconductor substrate, which can be a silicon substrate or other substrate used to form a semiconductor device. The embodiment of the present invention focuses on how to generate a stable emission current to effectively neutralize the positive charge on the surface of the ion beam and reduce the risk of arc discharge damage caused by ion implantation. The formation of the ion beam and the process related to ion implantation can adopt known processes, which will not be repeated in the embodiment.

[0031] like Figure 1 As shown, according to the ion implantation method of the embodiment of the present invention, in step S1, an ion beam of a set type for ion implantation is formed according to an ion implantation requirement, and the ion beam corresponds to an ion beam current.

[0032] The ion beam can be formed in step S1 by using a known ion beam generation method. For example, a suitable dopant, such as boron, boron difluoride, phosphorus or arsenic, can be selected according to the doping type to be formed in the semiconductor substrate, and the dopant is converted into a charged ion and accelerated to the required energy, and focused into an ion beam. As an example, the ion beam is formed by using an ion implanter produced by Applied Materials, and according to the charging condition of the ion beam, the current data corresponding to the ion beam, i.e., the ion beam current, can be detected and obtained.

[0033] like Figure 1 As shown, in step S2, electrons are emitted by an electron gun and plasma is generated separately, so that the electrons emitted by the electron gun collide with the plasma to form secondary electrons, and the secondary electrons move toward the ion beam under the attraction of the positive charges in the ion beam to form an emission current, and the secondary electrons neutralize the positive charges on the surface of the ion beam.

[0034] The electron gun may be a filament electron gun, a field emission electron gun or other electron guns suitable for emitting electrons. In the following embodiments, the electron gun is, for example, a filament electron gun, wherein the filament is, for example, a tungsten filament, and the emission parameters of the electron gun include the arc starting current of the filament electron gun. The plasma may be formed by treating an inert gas with a plasma generating device. In the following embodiments, the plasma is formed by, for example, using gas xenon (Xe), i.e., the plasma is xenon plasma.

[0035] The secondary electrons may be formed before, at the same time as, or after the ion beam is formed. In an embodiment of the present invention, after the ion beam and the emission current are formed, the secondary electrons are negatively charged and thus can neutralize the positive charge on the surface of the ion beam, thereby reducing the positive charge of the ion beam. When injected into a semiconductor substrate, it is not easy to form charge accumulation on the substrate surface, thereby reducing the risk of arc discharge damage caused by the positive charge accumulated on the substrate surface after ion injection.

[0036] Research has found that different ion beam currents, different electron gun emission parameters, or different gas flow rates for forming the plasma may all cause changes in the emission current. To this end, in this embodiment, based on different ion beam currents and different electron gun emission parameters, the relationship between different gas flow rates and the emission current is investigated, so that based on the ion beam current and the emission parameters of the electron gun, the emission current is adjusted according to the gas flow rate, so that the obtained emission current is stable. In addition, based on different ion beam currents and different gas flow rates, the relationship between different electron gun emission parameters and the emission current is investigated, so that based on the ion beam current and the gas flow rate, the emission current is adjusted according to the emission parameters of the electron gun, so that the obtained emission current is stable.

[0037] As an example, before forming the ion beam and the secondary electrons, the values ​​of the ion beam current, the emission parameters of the electron gun and the gas flow rate can be combined by setting multiple values ​​of the ion beam current, multiple emission parameters of the electron gun and multiple gas flow rates, and ion injection can be performed separately using the obtained multiple sets of data to obtain the detection value of the emission current corresponding to each set of data. The relationship between the emission current and the gas flow rate when the ion beam current and the emission parameters of the electron gun are specified values ​​is fitted to obtain a relationship related to the specified ion beam current and the emission parameters of the electron gun.

[0038] Reference Figure 2 , the above-mentioned acquisition of multiple sets of data and fitting may include the following process:

[0039] First, set a plurality of ion beam current data, a plurality of electron gun arc starting current data for generating electrons (such as Figure 2 AC1, AC2, AC3 and AC4) and multiple gas flow rates (taking Xe gas as an example) for forming plasma (such as 0.15 sccm, 0.2 sccm, 0.25 sccm, 0.3 sccm, 0.35 sccm, 0.4 sccm, 0.45 sccm);

[0040] Then, the plurality of ion beam current data, the plurality of arc starting current data and the plurality of gas flow rate data are combined to form a plurality of data sets, each of which includes a specified ion beam current, a specified arc starting current and a specified gas flow rate;

[0041] Next, each set of data is used to perform an ion implantation process using a dummy wafer, and the corresponding emission current data formed by secondary electrons is obtained through the charge monitor function of the ion implantation equipment;

[0042] Afterwards, each set of data and the corresponding emission current data are presented in a graphical form and data fitting is performed.

[0043] like Figure 2 As shown, it shows the emission current points corresponding to different gas flow rates in the two-dimensional coordinate system under different arc starting current data when the ion beam current is the set value. For a specified arc starting current, the relationship between the gas flow rate and the corresponding emission current can be fitted by a polynomial quadratic function to obtain the relationship I EC =ax 2 +bx+c, where I EC represents the emission current, x represents the gas flow rate, and a, b and c are fitting coefficients. Figure 2 As shown, for a specified arc starting current AC4, the fitting curve between the gas flow rate and the corresponding emission current (indicated by the yellow dotted line) satisfies the relationship I EC =a1x 2 +b1x+c1, where a1, b1, c1 are fitting coefficients related to the ion beam current and the arc starting current AC4 used in the experiment; for the specified arc starting current AC3, the fitting curve between the gas flow rate and the corresponding emission current (represented by the gray dotted line) satisfies the relationship I EC =a2x 2 +b2x+c2, where a2, b2, and c2 are fitting coefficients. It can be seen that for different specified arc starting currents, the combination of a1, b1, and c1 is different from the combination of a2, b2, and c2, so the corresponding relationship I EC =ax 2 +bx+c has a difference.

[0044] In addition, by examining the relationship between different emission parameters of the electron gun (arcing current in this embodiment) and the corresponding emission current under different gas flow data when the ion beam current is the set value, it can be obtained by fitting a polynomial quadratic function that the arcing current and the corresponding emission current satisfy the relationship I EC =a′y 2 +b′y+c′y, where I EC represents the emission current, y represents the arc starting current, and a′, b′ and c′ are fitting coefficients. Thus, when forming the emission current in step S2, the corresponding relationship I can be used based on the ion beam current and the gas flow rate for forming the plasma. EC=a′y 2 +b′y+c′y adjusts the arc starting current of the filament electron gun to obtain the corresponding emission current.

[0045] Since the ion beam current has an influence on the emission current, before forming the ion beam and the secondary electrons, multiple emission parameters of the electron gun and multiple values ​​of the gas flow rate can be set without setting the ion beam, and the emission parameters of the electron gun and the values ​​of the gas flow rate can be combined to obtain the detection value of the emission current corresponding to each set of data. Afterwards, the detection values ​​of the emission current can be compared when the ion beam is set and when the ion beam is not set when other conditions are the same, so as to analyze the influence of the ion beam on the emission current when other conditions are the same.

[0046] In the above embodiment, the relationship between the ion beam current, the emission parameters of the electron gun and the gas flow rate is used. EC =ax 2 +bx+c and I EC =a′y 2 +b′y+c′y, quantifies the factors affecting the emission current. When adjusting the emission current, the corresponding relationship I is selected according to the setting of the ion beam current, the emission parameters of the electron gun and the gas flow rate. EC =ax 2 +bx+c or I EC =a′y 2 +b′y+c′y is used to adjust the emission current. During the adjustment, the influence of factors other than the variables involved in the relationship on the emission current is reduced, which can improve the stability of the emission current, help ensure the effect of the emission current in neutralizing the positive charge on the surface of the ion beam, and reduce the risk of arc discharge damage caused by ion implantation.

[0047] Research has found that when the emission current is greater than the ion beam current, the MOS device formed on the substrate is not prone to arc discharge during operation. Therefore, in step S2, when forming the emission current, the emission current and the current ion beam current can be adjusted to satisfy the relationship I EC / I IC >N, in order to improve the effect of the emission current on neutralizing the positive charge on the surface of the ion beam, wherein I EC represents the emission current, I IC represents the ion beam current, and N is an integer greater than or equal to 1 (for example, 1).

[0048] After completing the above fitting, the relationship equations corresponding to different ion beam currents, different emission parameters of the electron gun, and different gas flow rates and the corresponding fitting coefficients can be stored in a database. In this way, when forming the emission current, the corresponding relationship equation I can be selected based on the set ion beam current and the emission parameters of the electron gun. EC =ax 2 +bx+c, using the relationship I EC =ax 2 + bx + c, adjust the gas flow rate (i.e., the value of x) to obtain the corresponding emission current. For example, the emission current can be adjusted to satisfy I EC / I IC >N, and, based on the set ion beam current and the gas flow rate, the corresponding relationship I can be selected EC =a′y 2 +b′y+c′y, using the relationship I EC =a′y 2 +b′y+c′y, adjust the arc starting current (i.e., the value of y) to obtain the corresponding emission current. For example, the emission current can be adjusted to satisfy I EC / I IC >N, so as to ensure the effect of neutralizing the positive charge on the surface of the ion beam by the emission current. The emission current is formed by the above method, and the adjustment efficiency is fast and the adjustment accuracy is high.

[0049] The embodiment of the present invention also relates to an ion implantation device. Figure 3 The ion beam device includes an ion beam module and an emission current module; the ion beam module is used to form an ion beam for ion implantation according to the ion implantation requirements, the ion beam has a positive charge and corresponds to an ion beam current; the electron flow module is used to emit electrons using an electron gun and generate plasma in addition, so that the electrons emitted by the electron gun collide with the plasma to form secondary electrons, and the secondary electrons move toward the ion beam under the attraction of the positive charge in the ion beam to form an emission current, and the secondary electrons neutralize the positive charge on the surface of the ion beam, wherein, when forming the emission current, based on the ion beam current and the emission parameters of the electron gun, the corresponding relationship I is used. EC =ax 2 +bx+c adjusts the gas flow rate of forming the plasma to obtain the corresponding emission current, I EC represents the emission current, x represents the gas flow rate, and a, b and c are fitting coefficients.

[0050] As an example, the electron gun adopts a filament electron gun, and the emission parameters of the electron gun include the arc starting current of the filament electron gun. When forming the emission current, the corresponding relationship I can also be used based on the ion beam current and the gas flow rate of forming the plasma. EC =a′y 2 +b′y+c′y adjusts the arc starting current of the filament electron gun to obtain the corresponding emission current, I EC represents the emission current, y represents the arc starting current, and a′, b′ and c′ are fitting coefficients.

[0051] In order to ensure the neutralization effect, when forming the emission current, it can be set so that the emission current and the current ion beam current satisfy the relationship I EC / I IC >N,I EC represents the emission current, I IC represents the ion beam current, and N is an integer greater than or equal to 1.

[0052] like Figure 3 As shown, the ion implantation apparatus may further include a database module, wherein the database module is used to store the relationship I related to different ion beam currents, different emission parameters of the electron gun or different gas flow rates. EC =ax 2 +bx+c and / or the relation I EC =a′y 2 When forming the emission current, the corresponding relational expression I can be called from the database module based on the set ion beam current and the emission parameters of the electron gun. EC =ax 2 +bx+c, using the relationship I EC =ax 2 + bx + c, adjust the gas flow rate (i.e., the value of x) to obtain the corresponding emission current. For example, the emission current can be adjusted to satisfy I EC / I IC >N, and, based on the set ion beam current and the gas flow rate, the corresponding relational expression I can be called from the database module EC =a′y 2 +b′y+c′y, using the relationship I EC =a′y 2 +b′y+c′y, adjust the arc starting current (i.e., the value of y) to obtain the corresponding emission current. For example, the emission current can be adjusted to satisfy I EC / I IC>N to ensure the effect of the emission current neutralizing the positive charge on the surface of the ion beam.

[0053] In the ion implantation method and ion implantation device described in the above embodiments, the secondary electrons formed by the electron gun and the plasma move toward the ion beam and can neutralize the positive charge on the surface of the ion beam. In addition, when forming the emission current, based on the ion beam current and the emission parameters of the electron gun, the corresponding relationship I is used. EC =ax 2 + bx + c adjusts the gas flow rate of forming the plasma to obtain the corresponding emission current, and based on the ion beam current and the gas flow rate of forming the plasma, the corresponding relationship I EC =a′y 2 +b′y+c′y adjusts the arc starting current of the filament electron gun to obtain the corresponding emission current, thereby facilitating obtaining a stable emission current, and utilizing the emission current to neutralize the positive charge on the surface of the ion beam, which helps to reduce the risk of arc discharge damage caused by ion implantation. In addition, utilizing the above relationship to adjust and form the required emission current has fast adjustment efficiency and high adjustment accuracy.

Claims

1. An ion implantation method, characterized in that: include: forming an ion beam for ion implantation according to an ion implantation requirement, wherein the ion beam has a positive charge and corresponds to an ion beam current; Using an electron gun to emit electrons and generate plasma, the electrons emitted by the electron gun collide with the plasma to form secondary electrons, the secondary electrons move toward the ion beam under the attraction of positive charges in the ion beam to form an emission current, and the secondary electrons neutralize the positive charges on the surface of the ion beam; Wherein, when forming the emission current, based on the ion beam current and the emission parameters of the electron gun, the corresponding relation I is used. EC =ax 2 +bx+c adjusts the gas flow rate of forming the plasma to obtain the corresponding emission current, I EC represents the emission current, x represents the gas flow rate, and a, b and c are fitting coefficients.

2. The ion implantation method according to claim 1, wherein: The electron gun is a filament electron gun, and the emission parameters of the electron gun include the arc starting current of the filament electron gun.

3. The ion implantation method according to claim 2, characterized in that: When forming the emission current, based on the ion beam current and the gas flow rate for forming the plasma, the corresponding relationship I is used. EC =a′y 2 +b′y+c′y adjusts the arc starting current of the filament electron gun to obtain the corresponding emission current, I EC represents the emission current, y represents the arc starting current, and a′, b′ and c′ are fitting coefficients.

4. The ion implantation method according to claim 1, wherein: When forming the emission current, the emission current and the current ion beam current satisfy the relationship I EC / I IC >N,I EC represents the emission current, I IC represents the ion beam current, and N is an integer greater than or equal to 1.

5. The ion implantation method according to claim 1, wherein: Before forming the ion beam and the secondary electrons, the values ​​of the ion beam current, the emission parameters of the electron gun and the gas flow rate are combined by setting a plurality of values ​​of the ion beam current, a plurality of emission parameters of the electron gun and a plurality of values ​​of the gas flow rate, and ion implantation processes are performed respectively using the obtained multiple sets of data to obtain the detection value of the emission current corresponding to each set of data, and the relationship between the emission current and the gas flow rate is fitted when the ion beam current and the emission parameters of the electron gun are specified values ​​to obtain the corresponding values ​​of a, b and c.

6. The ion implantation method according to claim 1, wherein: Before forming the ion beam and the secondary electrons, without setting the ion beam, multiple emission parameters of the electron gun and multiple values ​​of the gas flow are set, the emission parameters of the electron gun and the values ​​of the gas flow are combined, and the detection value of the emission current corresponding to each set of data is obtained.

7. An ion implantation device, characterized in that: include: An ion beam module, used for forming an ion beam for ion implantation according to ion implantation requirements, wherein the ion beam has a positive charge and corresponds to an ion beam current; as well as An electron flow module, used for emitting electrons by using an electron gun and generating plasma, so that the electrons emitted by the electron gun collide with the plasma to form secondary electrons, and the secondary electrons move toward the ion beam under the attraction of positive charges in the ion beam to form an emission current, and the secondary electrons neutralize the positive charges on the surface of the ion beam; Wherein, when forming the emission current, based on the ion beam current and the emission parameters of the electron gun, the corresponding relation I is used. EC =ax 2 +bx+c adjusts the gas flow rate of forming the plasma to obtain the corresponding emission current, I EC represents the emission current, x represents the gas flow rate, and a, b and c are fitting coefficients.

8. The ion implantation apparatus according to claim 7, wherein: The electron gun is a filament electron gun, and the emission parameters of the electron gun include the arc starting current of the filament electron gun.

9. The ion implantation apparatus according to claim 8, wherein: When forming the emission current, based on the ion beam current and the gas flow rate for forming the plasma, the corresponding relationship I is used. EC =a′y 2 +b′y+c′y adjusts the arc starting current of the filament electron gun to obtain the corresponding emission current, I EC represents the emission current, y represents the arc starting current, and a′, b′ and c′ are fitting coefficients.

10. The ion implantation apparatus according to claim 9, wherein: Also includes: A database module for storing the relational expression I related to different ion beam currents, different emission parameters of the electron gun or different gas flow rates. EC =ax 2 +bx+c and / or the relation I EC =a′y 2 +b′y+c′y and the corresponding fitting coefficients.

11. The ion implantation apparatus according to claim 7, wherein: When forming the emission current, the emission current and the current ion beam current satisfy the relationship I EC / I IC >N,I EC represents the emission current, I IC represents the ion beam current, and N is an integer greater than or equal to 1.

Images