A method and system for controlling uniformity and stability of ion implantation

Abstract

The present invention relates to the field of semiconductor ion implantation technology, and specifically to a method and system for controlling the uniformity and stability of ion implantation. To solve the technical problem of poor ion beam stability and uniformity in the prior art during ion implantation, the present invention monitors the analyzer temperature in real time. When the temperature exceeds a temperature threshold, based on a comparison result between an initial ion beam uniformity value and a uniformity value threshold, it is selected whether to sequentially adjust the ion concentration, ion beam stability, and ion beam uniformity. In the above process, the ion concentration is first adjusted by adjusting the electrical parameters of the ion source, and then the operation of adjusting the ion beam stability by adjusting the analyzer current value is selected according to the ion beam current value, and then the operation of adjusting the ion beam uniformity value threshold by adjusting the electrical parameters of the ion source is selected. This method ensures the uniformity and stability of the ion beam and can improve product yield when applied to the ion implantation process.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor ion implantation, in particular to a method and system for controlling the uniformity and stability of ion implantation. Background Art

[0002] Ion implantation (IMP) involves using the analyzer's magnetic field to select specific charged ions drawn from an ion source. Through focusing, acceleration, and scanning, a doping reaction occurs on the wafer surface. During the ion implantation process, heat accumulation raises the chamber temperature. The curved analyzer surface is more susceptible to contact with the high-temperature charged ion beam, causing the temperature to rise gradually. This in turn affects the analyzer's magnetic field, leading to an unstable and uneven ion beam.

[0003] For example, in the ion implantation process of 6-inch wafers, the analyzer's magnetic field changes due to temperature increases, which can cause the implantation process to be interrupted or the beam current to be reduced. Furthermore, for wafers implanted with smaller doses, fewer scans are required. A sudden interruption of the process or a reduction in the beam current can increase the error in the actual implanted dose, reducing product yield and resulting in production capacity loss. Excessively hot analyzers are often cooled with cooling water, but the cooling effect of cooling water is not constant, and the sudden temperature changes and mechanical vibrations caused by repeated water changes can easily affect the stability of the analyzer's magnetic field, thereby affecting the uniformity and stability of the ion beam. Summary of the Invention

[0004] The object of the present invention is to provide a method and system for controlling the uniformity and stability of ion implantation.

[0005] The technical solutions of the present invention are as follows:

[0006] A method for controlling uniformity and stability of ion implantation includes the following operations:

[0007] S1. Obtain the analyzer temperature. If the temperature is greater than a threshold, obtain the ion beam current value as the initial ion beam current value; obtain the initial ion beam uniformity value based on the initial ion beam current value; determine whether the initial ion beam uniformity value is less than the uniformity value threshold; if not, perform the ion implantation process; if less, execute S2;

[0008] S2, adjusting the anode power supply voltage, or / and the source magnetic power supply current, or / and the process gas flow, or / and the bias current, or / and the anode power supply load current value of the ion source to make the ion concentration reach the concentration threshold, and executing S3;

[0009] S3. Obtain the difference between the ion beam current value after the ion concentration is adjusted and the initial ion beam current value, and determine whether the difference is greater than the current difference threshold; if so, adjust the analyzer current value so that the ion beam current value reaches the maximum ion beam current value, and the ion beam stability is greater than the stability threshold within the first time range after the analyzer current value is adjusted, and execute S4; if not, execute S4;

[0010] S4. Obtain the ion beam uniformity value after the sub-beam stability is greater than the stability threshold, as the uniformity value of the ion beam to be adjusted; determine whether the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold; if it is greater, perform the ion implantation process; if it is not greater, adjust the anode power supply voltage, or / and source magnetic power supply current, or / and process gas flow, or / and bias current, or / and anode power supply load current value of the ion source, so that the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold, and then perform the ion implantation process.

[0011] The specific operation of S2 is: increase the process gas flow rate and the anode power supply voltage to the first process gas flow rate threshold and the first anode power supply voltage threshold respectively, and then obtain the ion concentration; determine whether the ion concentration is equal to the concentration threshold; if it is equal, execute S3; if it is less than, increase the source magnetic power supply current to the first source magnetic power supply current, so that the ion concentration is equal to the concentration threshold; if it is greater than, reduce the anode power supply voltage to the second anode power supply voltage threshold, and then reduce the process gas flow rate to the second process gas flow rate threshold, so that the ion concentration is equal to the concentration threshold; the second anode power supply voltage threshold is less than the first anode power supply voltage threshold, and the second process gas flow rate threshold is less than the first process gas flow rate threshold.

[0012] When the ion concentration is not equal to the concentration threshold, the process of increasing the source magnetic power supply current, or reducing the anode power supply voltage to the second anode power supply voltage threshold, or reducing the process gas flow rate to the second process gas flow rate threshold also includes obtaining the anode power supply load current value of the ion source; when the anode power supply load current value is greater than the first anode power supply load current value, the bias current is reduced so that the anode power supply load current value is not greater than the first anode power supply load current value.

[0013] The operation of adjusting the analyzer current value in S3 is specifically as follows: the analyzer current value is increased several times with a fixed first analyzer current change amount, so that the ion beam current value increases to a point where the difference with the corresponding maximum ion beam current value is less than a difference threshold, and then the analyzer current value is increased several times with a dynamically changing second analyzer current change amount until the ion beam current value increases to the corresponding maximum ion beam current value; the current second analyzer current change amount is obtained based on the maximum ion beam current value, the ion beam current value after the previous increase, and the analyzer current value after the previous increase.

[0014] In S4, when the uniformity value of the ion beam to be adjusted is not greater than the uniformity value threshold, the uniformity difference between the uniformity value of the ion beam to be adjusted and the uniformity value threshold is obtained; it is determined whether the uniformity difference is greater than the uniformity difference threshold; if it is greater, the source magnetic power supply current is increased so that the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold; if it is not greater, after increasing the anode power supply voltage several times by the change amount of the first anode power supply voltage, the process gas flow is increased in a manner that the gas flow increase amount is gradually reduced, so that the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold.

[0015] The ion beam uniformity value is obtained based on the standard deviation and mean of the ion beam current within the monitoring time range.

[0016] In S3, ion beam stability = 1-2·(maximum ion beam current - minimum ion beam current) / (maximum ion beam current + minimum ion beam current)·100%.

[0017] An ion implantation uniformity and stability control system, used to implement the above-mentioned ion implantation uniformity and stability control method, comprising:

[0018] The analyzer temperature determination module is used to obtain the analyzer temperature. If the temperature is greater than the temperature threshold, the ion beam current value is obtained as the initial ion beam current value; based on the initial ion beam current value, the initial ion beam uniformity value is obtained; and whether the initial ion beam uniformity value is less than the uniformity value threshold is determined; if not, the ion implantation process is performed; if less, the ion concentration adjustment module is executed;

[0019] an ion concentration adjustment module, configured to adjust the anode power supply voltage, or / and the source magnetic power supply current, or / and the process gas flow, or / and the bias current, or / and the anode power supply load current value of the ion source so as to bring the ion concentration to a concentration threshold value and execute the ion beam stability adjustment module;

[0020] An ion beam stability adjustment module is configured to obtain the difference between the ion beam current value after the ion concentration is adjusted and the initial ion beam current value, and determine whether the difference is greater than a current difference threshold; if so, the ion beam current value is adjusted to reach a maximum ion beam current value for a corresponding time period by adjusting the analyzer current value, and the ion beam stability is greater than the stability threshold within a first time range after the analyzer current value is adjusted, and the ion beam uniformity adjustment module is executed; if not, the ion beam uniformity adjustment module is executed;

[0021] The ion beam uniformity adjustment module is used to obtain the ion beam uniformity value after the ion beam stability is greater than the stability threshold, as the ion beam uniformity value to be adjusted; determine whether the ion beam uniformity value to be adjusted is greater than the uniformity value threshold; if so, perform the ion implantation process; if not, adjust the anode power supply voltage, or / and source magnetic power supply current, or / and process gas flow, or / and bias current, or / and anode power supply load current value of the ion source, so that the ion beam uniformity value to be adjusted is greater than the uniformity value threshold, and then perform the ion implantation process.

[0022] The beneficial effects of the present invention are:

[0023] The present invention provides a method for controlling the uniformity and stability of ion implantation, which monitors the analyzer temperature in real time. When the temperature exceeds a temperature threshold, an initial ion beam uniformity value is obtained based on an initial ion beam current value, and according to a comparison result between the initial ion beam uniformity value and a uniformity value threshold, it is selected whether to sequentially perform the steps of adjusting the ion concentration, ion beam stability, and ion beam uniformity. In the above process, the ion concentration is first adjusted by adjusting the electrical parameters of the ion source, and then, according to the difference between the ion beam current value after the ion concentration adjustment and the ion beam current value, it is determined whether it is necessary to perform an operation of adjusting the analyzer current value to make the ion beam stability greater than the stability threshold, and then it is determined whether it is necessary to perform an operation of adjusting the electrical parameters of the ion source to make the ion beam uniformity greater than the uniformity value threshold. This method not only ensures the uniformity and stability of the ion beam, but also improves the flexibility of the ion beam uniformity and stability adjustment method. When applied in the ion implantation process, it can improve the product yield. DETAILED DESCRIPTION

[0024] This embodiment provides a method for controlling uniformity and stability of ion implantation, including the following operations:

[0025] S1. Obtain the analyzer temperature. If the temperature is greater than a threshold, obtain the ion beam current value as the initial ion beam current value; obtain the initial ion beam uniformity value based on the initial ion beam current value; determine whether the initial ion beam uniformity value is less than the uniformity value threshold; if not, perform the ion implantation process; if less, execute S2;

[0026] S2, adjusting the anode power supply voltage, or / and the source magnetic power supply current, or / and the process gas flow, or / and the bias current, or / and the anode power supply load current value of the ion source to make the ion concentration reach the concentration threshold, and executing S3;

[0027] S3. Obtain the difference between the ion beam current value after the ion concentration is adjusted and the initial ion beam current value, and determine whether the difference is greater than the current difference threshold; if so, adjust the analyzer current value so that the ion beam current value reaches the maximum ion beam current value, and the ion beam stability is greater than the stability threshold within the first time range after the analyzer current value is adjusted, and execute S4; if not, execute S4;

[0028] S4. Obtain the ion beam uniformity value after the sub-beam stability is greater than the stability threshold, as the uniformity value of the ion beam to be adjusted; determine whether the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold; if it is greater, perform the ion implantation process; if it is not greater, adjust the anode power supply voltage, or / and source magnetic power supply current, or / and process gas flow, or / and bias current, or / and anode power supply load current value of the ion source, so that the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold, and then perform the ion implantation process.

[0029] S1. Obtain the temperature of the analyzer. If the temperature is greater than the temperature threshold, obtain the ion beam current value as the initial ion beam current value; based on the initial ion beam current value, obtain the initial ion beam uniformity value; determine whether the initial ion beam uniformity value is less than the uniformity value threshold; if not, perform the ion implantation process; if less, execute S2.

[0030] Monitor the analyzer temperature in real time. When the temperature exceeds the temperature threshold, obtain the initial ion beam uniformity value based on the initial ion beam current value. Based on the comparison result between the initial ion beam uniformity value and the uniformity value threshold, choose whether to perform the uniformity adjustment step to ensure ion uniformity throughout the entire process, thereby ensuring the quality of subsequent ion implantation.

[0031] First, after cooling water is passed into the analyzer cavity, the ion source is controlled to generate ions based on the standard ion beam uniformity curve, and the analyzer is controlled to screen the ions, as well as the focusing, acceleration and scanning functions of the subsequent section to output the ion beam.

[0032] Then, to ensure the quality of subsequent ion implantation, the analyzer temperature is obtained in real time during the ion beam generation process. If the analyzer temperature is greater than the temperature threshold, the ion beam current value coming out of the analyzer is obtained (which can be achieved by focusing the Faraday cup) as the initial ion beam current value.

[0033] Next, based on the initial ion beam current value, the initial ion beam uniformity value is calculated. The ion beam uniformity value is calculated based on the standard deviation and mean ion beam current over the monitoring time range. Specifically, the ion beam uniformity value = 1 - (standard deviation / mean ion beam current) x 100%.

[0034] Finally, determine whether the initial ion beam uniformity value is less than the uniformity value threshold (preferably 99.5%); if not, perform the ion implantation process and implant the ion beam onto the wafer; if less, it indicates that the initial ion beam uniformity is low and the adjustment operation in S2 needs to be performed.

[0035] S2. Adjust the anode power supply voltage, or / and source magnetic power supply current, or / and process gas flow, or / and bias current, or / and anode power supply load current value of the ion source to make the ion concentration reach the concentration threshold, and execute S3.

[0036] When the initial ion beam uniformity is low, first adjust the ion concentration in the ion source arc chamber to provide a stable ion supply basis, optimize the working state of the ion source, make more positively charged ions repel each other, and facilitate the subsequent widening of the positively charged ion beam coming out of the analyzer, which is conducive to the subsequent rapid improvement of ion beam stability and uniformity.

[0037] Specifically, first, increase the process gas flow and anode power supply voltage of the ion source to quickly increase the ion concentration. When the process gas flow and anode power supply voltage reach the first process gas flow threshold and the first anode power supply voltage threshold respectively, obtain the ion concentration; then, determine whether the ion concentration is equal to the concentration threshold; if equal, directly execute S3 to improve work efficiency; if less than, increase the source magnetic power supply current to the first source magnetic power supply current to finely improve the ionization degree of the gas, and then finely increase the ion concentration so that the ion concentration is equal to the concentration threshold; if greater than, reduce the anode power supply voltage to the second anode power supply voltage threshold, reduce the process gas flow to the second process gas flow threshold, first quickly reduce the anode power supply voltage and then slowly reduce the process gas flow, so that the ion concentration slowly transitions to equal the concentration threshold.

[0038] The second anode power supply voltage threshold is smaller than the first anode power supply voltage threshold, and the second process gas flow rate threshold is smaller than the first process gas flow rate threshold.

[0039] The above ion concentrations can be measured using a setup cup located behind the analyzer. The principle of measurement is similar to that of a focusing Faraday cup, with the setup cup placed in front of the focusing Faraday cup.

[0040] In addition, in order to prevent excessive changes in ion concentration from having an adverse effect on the ion beam, when the ion concentration is not equal to the concentration threshold, the process of increasing the source magnetic power supply current, or reducing the anode power supply voltage to the second anode power supply voltage threshold, or reducing the process gas flow rate to the second process gas flow rate threshold, also includes real-time acquisition of the anode power supply load current value of the ion source; when the anode power supply load current value is greater than the first anode power supply load current value, the bias current is reduced so that the anode power supply load current value is not greater than the first anode power supply load current value (preferably 8A).

[0041] During the above process, the total increase in the anode power supply voltage is 10V, the total increase in the source magnetic power supply current is 1A, the increase rate of the process gas flow is 20%, the total decrease in the bias current is 0.1A, and the anode power supply load current value is less than 8A.

[0042] S3. Obtain the difference between the ion beam current value after the ion concentration is adjusted and the initial ion beam current value, and determine whether the difference is greater than the current difference threshold; if so, adjust the analyzer current value so that the ion beam current value reaches the maximum ion beam current value, and make the ion beam stability greater than the stability threshold within the first time range after the analyzer current value is adjusted, and execute S4; if not, execute S4.

[0043] When the ion concentration reaches the concentration threshold, the difference between the ion beam current value after ion concentration adjustment and the initial ion beam current value is used to determine whether the current ion beam is stable. If it is stable, the uniformity adjustment operation of S4 is directly executed; if it is unstable, the ion beam stability is brought to the standard by adjusting the analyzer current value.

[0044] Obtain the difference between the ion beam current value after ion concentration adjustment and the initial ion beam current value (the difference is the absolute value), and determine whether the difference is greater than a current difference threshold. The current difference threshold is preferably 5%.

[0045] If it is greater than, the analyzer current value is adjusted so that the ion beam current value reaches the maximum value of the ion beam current value in the corresponding time period in the standard ion beam uniformity curve, and the ion beam stability is greater than the stability threshold within the first time range after the analyzer current value is adjusted, and S4 is executed.

[0046] Specifically, the analyzer current value is increased several times with a fixed first analyzer current change (preferably 0.01A) to increase the ion beam current value until the difference with the corresponding maximum ion beam current value is less than the difference threshold, and then the analyzer current value is increased several times with a dynamically changing second analyzer current change to slowly approach the maximum ion beam current value until the ion beam current value increases to the corresponding maximum ion beam current value. This is also conducive to the ion beam stability quickly exceeding the stability threshold.

[0047] The above-mentioned operation of increasing the analyzer current value several times with a fixed first analyzer current change amount (preferably 0.01A) is specifically as follows: placing a focusing Faraday cup into the analyzer to block the ion beam, obtaining a measured ion beam current value, increasing the analyzer current value by 0.01A, and if the ion beam current value measured by the focusing Faraday cup increases, then the analyzer current value is further increased by 0.01A until the ion beam current value increases to a value where the difference from the corresponding maximum ion beam current value is less than a difference threshold.

[0048] At the same time, the above-mentioned second analyzer current change changes dynamically. The current second analyzer current change is obtained based on the maximum ion beam current value, the ion beam current value after the previous increase (the current initial ion beam current value), and the analyzer current value after the previous increase (the current analyzer current value).

[0049] The second analyzer current change can be obtained by the following formula:

[0050] ,

[0051] ΔI t,a For the t The second analyzer current change is the amount of the second analyzer current change, α is the adjustment coefficient, I t-1,a For the t-1 The analyzer current value after the increase is I t-1,c For the t-1 The increased ion beam current value, I max is the maximum value of the ion beam current, β is the ion beam current compensation coefficient.

[0052] The above-mentioned ion beam stability=1-2·(maximum ion beam current-minimum ion beam current) / (maximum ion beam current+minimum ion beam current)·100%.

[0053] In addition, if the ion beam current value reaches the maximum ion beam current value of the corresponding time period by adjusting the analyzer current value, and the ion beam stability is not greater than the stability threshold within the first time range after the analyzer current value is adjusted, the analyzer current value is first increased and then decreased, and the execution is repeated for several rounds until the ion beam stability is greater than the stability threshold; in each round, the increase in the analyzer current value is greater than the decrease; and the increase and decrease in the analyzer current value in several rounds are successively reduced, thereby making the ion beam current value at a larger value narrow the gap between the ion beam current values ​​at different times within the first time range after the analyzer current value is adjusted, so as to quickly make the ion beam stability greater than the stability threshold.

[0054] S4. Obtain the ion beam uniformity value after the ion beam stability is greater than the stability threshold, as the uniformity value of the ion beam to be adjusted; determine whether the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold; if it is greater, perform the ion implantation process; if it is not greater, adjust the anode power supply voltage, or / and source magnetic power supply current, or / and process gas flow, or / and bias current, or / and anode power supply load current value of the ion source, so that the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold, and then perform the ion implantation process.

[0055] When the ion beam stability is greater than the stability threshold, first determine whether the ion beam uniformity (uniformity value of the ion beam to be adjusted) meets the standard. If it meets the standard, the ion implantation process is directly carried out; if it does not meet the standard, the electrical parameters of the ion source are adjusted to make the ion beam uniformity greater than the uniformity value threshold, and then the ion implantation process is carried out.

[0056] An ion beam uniformity value after the ion beam stability is greater than a stability threshold is obtained as the uniformity value of the ion beam to be adjusted; and whether the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold is determined.

[0057] If it is greater than, an ion implantation process is performed to implant an ion beam onto the wafer.

[0058] If it is not greater than, adjust the anode power supply voltage, or / and source magnetic power supply current, or / and process gas flow, or / and bias current, or / and anode power supply load current value of the ion source so that the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold, and then perform the ion implantation process.

[0059] Specifically, when the uniformity value of the ion beam to be adjusted is not greater than the uniformity value threshold, a uniformity difference between the uniformity value of the ion beam to be adjusted and the uniformity value threshold is obtained; and it is determined whether the uniformity difference is greater than the uniformity difference threshold.

[0060] If it is greater than, it means that the uniformity value of the ion beam to be adjusted is significantly different from the uniformity value threshold. Therefore, by increasing the source magnetic power supply current and changing the magnetic field strength and distribution of the ion source, the uniformity of the ion beam is directly affected, so that the uniformity value of the ion beam to be adjusted quickly exceeds the uniformity value threshold.

[0061] If it is not greater than, then after increasing the anode power supply voltage several times by the change in the first anode power supply voltage, the process gas flow rate is increased in a manner that the gas flow rate increase is gradually reduced, and the intensity and distribution of the ion beam are slowly and appropriately changed, thereby changing the uniformity so that the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold.

[0062] In addition, the above-mentioned process of increasing the source magnetic power supply current, or increasing the anode power supply voltage several times, or increasing the process gas flow rate also includes real-time acquisition of the anode power supply load current value of the ion source; when the anode power supply load current value is greater than the second anode power supply load current value, the bias current is reduced so that the anode power supply load current value is not greater than the second anode power supply load current value (preferably 9A).

[0063] During the above process, the total increase in the anode power supply voltage is 5V, the total increase in the source magnetic power supply current is 0.5A, the increase rate of the process gas flow is 20%, the total decrease in the bias current is 0.1A, and the anode power supply load current value is less than 9A.

[0064] This embodiment further provides an ion implantation uniformity and stability control system, which is used to implement the above-mentioned ion implantation uniformity and stability control method, including:

[0065] The analyzer temperature determination module is used to obtain the analyzer temperature. If the temperature is greater than the temperature threshold, the ion beam current value is obtained as the initial ion beam current value; based on the initial ion beam current value, the initial ion beam uniformity value is obtained; and whether the initial ion beam uniformity value is less than the uniformity value threshold is determined; if not, the ion implantation process is performed; if less, the ion concentration adjustment module is executed;

[0066] an ion concentration adjustment module, configured to adjust the anode power supply voltage, or / and the source magnetic power supply current, or / and the process gas flow, or / and the bias current, or / and the anode power supply load current value of the ion source so as to bring the ion concentration to a concentration threshold value and execute the ion beam stability adjustment module;

[0067] An ion beam stability adjustment module is configured to obtain the difference between the ion beam current value after the ion concentration is adjusted and the initial ion beam current value, and determine whether the difference is greater than a current difference threshold; if so, the ion beam current value is adjusted to reach a maximum ion beam current value for a corresponding time period by adjusting the analyzer current value, and the ion beam stability is greater than the stability threshold within a first time range after the analyzer current value is adjusted, and the ion beam uniformity adjustment module is executed; if not, the ion beam uniformity adjustment module is executed;

[0068] The ion beam uniformity adjustment module is used to obtain the ion beam uniformity value after the ion beam stability is greater than the stability threshold, as the ion beam uniformity value to be adjusted; determine whether the ion beam uniformity value to be adjusted is greater than the uniformity value threshold; if so, perform the ion implantation process; if not, adjust the anode power supply voltage, or / and source magnetic power supply current, or / and process gas flow, or / and bias current, or / and anode power supply load current value of the ion source, so that the ion beam uniformity value to be adjusted is greater than the uniformity value threshold, and then perform the ion implantation process.

[0069] The present embodiment provides a method for controlling the uniformity and stability of ion implantation, which monitors the analyzer temperature in real time. When the temperature exceeds a temperature threshold, an initial ion beam uniformity value is obtained based on an initial ion beam current value, and based on a comparison result between the initial ion beam uniformity value and a uniformity value threshold, it is selected whether to sequentially perform the steps of adjusting the ion concentration, ion beam stability, and ion beam uniformity. In the above process, the ion concentration is first adjusted by adjusting the electrical parameters of the ion source, and then, based on the difference between the ion beam current value after the ion concentration adjustment and the ion beam current value, it is determined whether it is necessary to perform an operation of adjusting the analyzer current value to make the ion beam stability greater than the stability threshold, and then it is determined whether it is necessary to perform an operation of adjusting the electrical parameters of the ion source to make the ion beam uniformity greater than the uniformity value threshold. This method not only ensures the uniformity and stability of the ion beam, but also improves the flexibility of the ion beam uniformity and stability adjustment method. When applied to the ion implantation process, it can improve the product yield.

Claims

1. A method for controlling uniform stability of ion implantation, characterized in that: The following operations are included: S1. Obtain the temperature of the analyzer. If the temperature is greater than a threshold, obtain an ion beam current value as an initial ion beam current value; obtain an initial ion beam uniformity value based on the initial ion beam current value; and determine whether the initial ion beam uniformity value is less than a uniformity value threshold. If it is not less than, perform ion implantation process; If it is less, execute S2; S2, adjusting the anode power supply voltage, or / and the source magnetic power supply current, or / and the process gas flow, or / and the bias current, or / and the anode power supply load current value of the ion source to make the ion concentration reach the concentration threshold, and executing S3; S3, obtaining the difference between the ion beam current value after the ion concentration is adjusted and the initial ion beam current value, and determining whether the difference is greater than a current difference threshold; If it is greater than, adjust the analyzer current value so that the ion beam current value reaches the maximum ion beam current value, and make the ion beam stability greater than the stability threshold within the first time range after the analyzer current value is adjusted, and execute S4; If not, execute S4; S4. Obtaining an ion beam uniformity value after the ion beam stability is greater than a stability threshold value as the ion beam uniformity value to be adjusted; Determining whether the uniformity value of the ion beam to be adjusted is greater than a uniformity value threshold; If it is greater than, ion implantation process is performed; If not, adjusting the anode power supply voltage, or / and the source magnetic power supply current, or / and the process gas flow, or / and the bias current, or / and the anode power supply load current value of the ion source so that the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold, and then performing the ion implantation process; The ion beam uniformity value is obtained based on the standard deviation and mean value of the ion beam current within the monitoring time range; Ion beam stability = 1-2·(maximum ion beam current - minimum ion beam current) / (maximum ion beam current + minimum ion beam current)·100%.

2. The method for controlling uniformity and stability of ion implantation according to claim 1, wherein: The operation of S2 is specifically as follows: After increasing the process gas flow rate and the anode power supply voltage to a first process gas flow rate threshold and a first anode power supply voltage threshold, respectively, obtaining the ion concentration; and determining whether the ion concentration is equal to the concentration threshold; If they are equal, execute S3; If it is less than, increasing the source magnetic power supply current to the first source magnetic power supply current to make the ion concentration equal to the concentration threshold; If it is greater than, after reducing the anode power supply voltage to a second anode power supply voltage threshold, reducing the process gas flow rate to a second process gas flow rate threshold, so that the ion concentration is equal to the concentration threshold; The second anode power supply voltage threshold is smaller than the first anode power supply voltage threshold, and the second process gas flow rate threshold is smaller than the first process gas flow rate threshold.

3. The method for controlling uniformity and stability of ion implantation according to claim 2, wherein: When the ion concentration is not equal to the concentration threshold, the process of increasing the source magnetic power supply current, or reducing the anode power supply voltage to the second anode power supply voltage threshold, or reducing the process gas flow rate to the second process gas flow rate threshold also includes obtaining the anode power supply load current value of the ion source; when the anode power supply load current value is greater than the first anode power supply load current value, the bias current is reduced so that the anode power supply load current value is not greater than the first anode power supply load current value.

4. The method for controlling uniformity and stability of ion implantation according to claim 1, wherein: The operation of adjusting the analyzer current value in S3 is specifically as follows: increasing the analyzer current value several times with a fixed first analyzer current variation until the ion beam current value increases to a value where the difference between the ion beam current value and the corresponding maximum ion beam current value is less than a difference threshold, and then increasing the analyzer current value several times with a dynamically changing second analyzer current variation until the ion beam current value increases to the corresponding maximum ion beam current value; The second analyzer current variation amount at this time is obtained based on the maximum ion beam current value, the ion beam current value after the previous increase, and the analyzer current value after the previous increase.

5. The method for controlling uniformity and stability of ion implantation according to claim 1, wherein: In the step S4, when the uniformity value of the ion beam to be adjusted is not greater than the uniformity value threshold, obtaining a uniformity difference between the uniformity value of the ion beam to be adjusted and the uniformity value threshold; and determining whether the uniformity difference is greater than the uniformity difference threshold. If it is greater than, increase the source magnetic power supply current so that the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold; If not, after increasing the anode power supply voltage several times by the first anode power supply voltage change, the process gas flow is increased by gradually decreasing the gas flow increase, so that the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold.

6. A uniformity and stability control system for ion implantation, used in the uniformity and stability control method for ion implantation according to claim 1, characterized in that: include: The analyzer temperature judgment module is used to obtain the analyzer temperature. If the temperature is greater than the temperature threshold, the ion beam current value is obtained as the initial ion beam current value; Obtaining an initial ion beam uniformity value based on an initial ion beam current value; and determining whether the initial ion beam uniformity value is less than a uniformity value threshold; If it is not less than, perform ion implantation process; If it is less than, the ion concentration adjustment module is executed; an ion concentration adjustment module, configured to adjust the anode power supply voltage, or / and the source magnetic power supply current, or / and the process gas flow, or / and the bias current, or / and the anode power supply load current value of the ion source so as to bring the ion concentration to a concentration threshold value and execute the ion beam stability adjustment module; An ion beam stability adjustment module is configured to obtain a difference between the ion beam current value after ion concentration adjustment and the initial ion beam current value, and determine whether the difference is greater than a current difference threshold; if so, the ion beam current value is adjusted by adjusting the analyzer current value so that the ion beam current value reaches a maximum ion beam current value for the corresponding time period, and the ion beam stability is greater than the stability threshold within a first time range after the analyzer current value is adjusted, and the ion beam uniformity adjustment module is executed; If not, execute the ion beam uniformity adjustment module; An ion beam uniformity adjustment module is used to obtain an ion beam uniformity value after the ion beam stability is greater than a stability threshold value as the ion beam uniformity value to be adjusted; Determine whether the uniformity value of the ion beam to be adjusted is greater than a uniformity value threshold; if so, perform an ion implantation process; If it is not greater than, adjust the anode power supply voltage, or / and source magnetic power supply current, or / and process gas flow, or / and bias current, or / and anode power supply load current value of the ion source so that the uniformity value of the ion beam to be adjusted is greater than the uniformity value threshold, and then perform the ion implantation process.