Method for automatic dose uniformity control using multi-pole magnet rod spacing
By combining multi-pole magnetic rod spacing control with bidirectional measurement mode, the problem of ion beam dose uniformity adjustment in semiconductor manufacturing has been solved, achieving efficient and precise dose uniformity adjustment, adapting to different beam states, and improving the consistency of semiconductor device performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING SHUOKE ZHONGKEXIN ELECTRONICS EQUIP CO LTD
- Filing Date
- 2019-10-15
- Publication Date
- 2026-05-12
AI Technical Summary
In the semiconductor manufacturing process, as the wafer size increases, it becomes difficult to effectively adjust the dose uniformity of the ion beam in the ion implanter, which affects the consistency of device performance.
An automatic adjustment method using multi-pole magnetic rod spacing control is adopted. Data is collected through a moving Faraday bidirectional measurement mode, and the magnetic pole spacing is optimized by combining the least squares method and iterative calculation to achieve uniformity adjustment of the ion beam.
It significantly improves the efficiency and accuracy of ion beam dose uniformity adjustment, shortens the adjustment time, has a wide range of applications, adapts to different beam states, and achieves rapid and reliable dose uniformity adjustment.
Smart Images
Figure CN112670147B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor equipment manufacturing, and in particular to a technology for automatically adjusting the uniformity of ion beam dose using multi-pole magnetic rod spacing control in an ion implanter. Background Technology
[0002] With the development of semiconductor integrated circuit manufacturing processes, higher demands are placed on the performance of semiconductor manufacturing equipment. Among semiconductor manufacturing equipment, the ion implanter is a core doping device in semiconductor device manufacturing, mainly used to change the conductivity type and voltage of the target material through doping. As wafer sizes enter the 300mm era, and advanced device manufacturing processes continue to advance to 7nm and 5nm, to ensure the consistency of device performance across the entire wafer, higher requirements must be placed on the uniformity indicators in the ion implantation doping process. Therefore, achieving automatic adjustment of ion beam dose uniformity has become particularly important. Based on the above requirements, this invention proposes a method for automatically adjusting dose uniformity using multi-pole magnetic rod spacing control, realizing automatic adjustment of ion beam dose uniformity. Summary of the Invention
[0003] This invention proposes a novel method for automatically adjusting dose uniformity by controlling the spacing of multi-pole magnetic rods in existing ion implantation technology, providing reliable and effective support for terminal ion implantation.
[0004] This invention is achieved through the following scheme:
[0005] The initial value of the ion beam J0(1) was measured when the positions of the multiple magnetic poles remained unchanged; the distance between the magnetic rods was increased or decreased by the same amount for each of the 2n magnetic poles (referred to as the magnetic rod spacing), and the ion beam value corresponding to each magnetic pole was collected. It can also collect the response beam values of two non-interfering magnetic poles at once, reducing the number of Faraday motions. In order to further improve the efficiency of data acquisition, the traditional Faraday motion mode is changed from the original unidirectional measurement mode to a bidirectional measurement mode, saving about half the time on the original basis. During the data acquisition process, abnormal situations such as sudden beam interruption or no beam may occur. The algorithm has filtered the above abnormal data to ensure the stability of the data and the continuity of the program (2); the amplitude relationship between the response of the magnetic pole and the spacing of the magnetic rod is calculated based on the acquired data. Assuming that the increment of the magnetic rod spacing is equal to Δd, its mathematical model expression is:
[0006] ;
[0007] in and Let ai, xi, and wi represent the response current density difference and current density when the increment of the j-th magnetic pole is Δd, respectively. ai, xi, and wi are all mathematical model coefficients of the response of the i-th magnetic pole, which can be obtained by fitting algorithm. Analyzing the mathematical model formula, different initial current densities J0 correspond to different response curves. A new J0 can be replaced during the iteration process to perform iterative calculation, which further improves the calculation speed of the algorithm (3). Using the least squares method, based on the average value of each initial beam current, Solve the overdetermined equations to calculate the optimal spacing between the magnetic rods for each magnetic pole (4); the machine reads the calculation results, outputs the beam current value, and verifies the debugging effect (5).
[0008] Three adjustment modes are designed: multi-pole up-adjustment mode, multi-pole down-adjustment mode, and multi-pole full-adjustment mode. The optimal adjustment mode is selected based on the current beam state to adjust the dose uniformity.
[0009] The present invention has the following significant advantages:
[0010] 1) Data acquisition using the moving Faraday bidirectional measurement mode saves about half the time compared to the unidirectional mode;
[0011] 2) By simultaneously acquiring response data from two magnetic poles and performing iterative calculations, the efficiency of regulation is greatly improved while ensuring calculation accuracy;
[0012] 3) This invention automatically selects the adjustment method based on the current beam state, has a wide range of applications, a large adjustment range, and can quickly complete the target adjustment by embedding it into the machine through a C language program; Attached Figure Description
[0013] To facilitate a more comprehensive understanding of the present invention, reference is now made to the accompanying drawings.
[0014] Figure 1 A flowchart illustrating the motion mode of the mobile Faraday bidirectional measurement involved in this invention is presented.
[0015] Figure 2 A schematic diagram illustrating the actual response curves of the lower magnetic poles 3 and 9 in the embodiments of the present invention.
[0016] Figure 3 The flowchart illustrates the algorithm program for adjusting dose uniformity using multiple magnetic poles involved in this invention.
[0017] Figure 4 A flowchart illustrating the adjustment steps involved in this invention is provided. Detailed Implementation
[0018] The present invention will be further described below with reference to specific embodiments in conjunction with the accompanying drawings.
[0019] See Figure 1 The flowchart of the bidirectional measurement mode of the moving Faraday involved in this invention improves the data acquisition speed in the algorithm by changing the movement mode of the moving Faraday. A set of programs for the bidirectional measurement mode of the moving Faraday is designed in the motion control system of the moving Faraday. First, the bidirectional measurement mode of the moving Faraday is entered (1), and the bidirectional measurement mode start command is issued. Then, by issuing the moving Faraday movement command n times, the moving Faraday can complete the forward data acquisition and the reverse data acquisition in sequence, and repeat step (2). When the n data acquisitions are completed or the algorithm automatically adjusts and ends, the exit from the bidirectional measurement mode of the moving Faraday needs to be issued (3) to ensure that the moving Faraday returns to a safe position. Compared with the unidirectional measurement mode of the moving Faraday, the bidirectional measurement mode saves about half of the time in data acquisition.
[0020] See Figure 2 The schematic diagram of the actual response curves of the lower magnetic poles 3 and 9 involved in this invention is obtained by simultaneously increasing the same magnetic rod spacing (e.g., Δd = 2 mm) of the lower magnetic poles 3 (2) and 9 (1) through an embodiment. Region (1) represents the response waveform of the lower magnetic pole 9. The Gaussian model formula is used to construct this response waveform curve. Fitting revealed that, under the same initial ion beam J0, the response waveform curve is linearly related to the adjustment increment. The algorithm's adjustment is based on this linear relationship. Region (2) represents the response waveform curve of the lower magnetic pole 3, which also satisfies the above-mentioned basic condition. The remaining magnetic poles can be obtained similarly. Based on the response waveform curves of the magnetic poles to the ion beam, an initial coefficient matrix for adjusting the uniformity of the ion beam is established.
[0021] See Figure 3 The algorithm flowchart involved in this invention measures the ion beam current value J0(1) when the magnetic pole position remains unchanged, and determines whether J0 is a normal value to ensure the stability of the algorithm. The ion beam current values of every two non-interfering magnetic poles are sequentially collected with the same increase in magnetic rod spacing. At the same time, each set of data is required to determine whether it is a normal value. If an abnormality occurs, the data is re-collected, only from the current abnormal magnetic pole position. The amplitude relationship between the magnetic pole response and the magnetic rod spacing is calculated (3). The first calculation passes. The results show that calculations using real data are superior to those using data processed through fitting or other techniques. Subsequent iterative calculations do not require further data collection, based on the mathematical model. The data in the iteration, i.e., the coefficient matrix, is only related to the initial value J0 of the ion beam. A new coefficient matrix is calculated using this relationship, saving the time spent on data acquisition during the iteration process. The number of iterations is set to less than L, which can be adjusted according to actual needs. Based on the average value of the initial value (1) of the ion beam... Solving the overdetermined equations yields the optimal spacing between the magnetic rods for each magnetic pole (4). Finally, the machine can read the calculated results and output the beam current value by moving the Faraday motion. The effect of the algorithm on beam regulation after adjusting multiple magnetic poles was verified.
[0022] See Figure 4 The flowchart of the adjustment steps involved in this invention is a summary of the algorithm and a large number of experimental results on the instrument line, resulting in an automatic dose uniformity adjustment flowchart. First, the non-uniformity value Tmpsigma (the standard deviation of the ion beam within the adjustable range of the current ion beam) is read to determine if it has entered the multi-pole fine adjustment range. If not, the multi-pole full adjustment mode is activated, which has a strong adjustment force and can quickly adjust to below the required value. When the initial value is less than this range, the current energy mode needs to be determined first. For high-energy modes, for faster and more effective adjustment, the first step is to adjust the multi-pole up-adjustment mode, followed by the multi-pole down-adjustment mode, and then the multi-pole full-adjustment mode. If any adjustment has reached below the target value, the adjustment is successful, and the automatic adjustment program exits. If the target value still cannot be reached following the above adjustment process, the adjustment mode can be freely selected for adjustment, or the automatic adjustment can be exited for manual intervention. Because the beam state in high-energy modes is relatively stable, in most cases, only the multi-pole up-adjustment or down-adjustment mode needs to be activated to reach the target value, saving about half the time compared to full adjustment. In low-energy mode, the beam state is relatively divergent, requiring multiple full-adjustment cycles to complete the adjustment. If the target value is not reached after three iterations (the number of iterations mentioned above can be set according to the actual situation), the adjustment mode can be freely selected, or automatic adjustment can be exited for manual intervention. After each adjustment in any adjustment mode, the adjustment effect is evaluated. If the non-uniformity value after adjustment is greater than before, the adjustment is invalid, and the previous adjustment result should be returned; if the adjustment is effective, subsequent adjustments continue. See details for the specific process. Figure 4 .
[0023] The foregoing has provided a detailed description of the present invention. Any person skilled in the art who, without departing from the spirit of the present invention, makes slight modifications or alterations to the methods and techniques disclosed above to create equivalent embodiments, but any simple modifications, equivalent changes, or alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention's technical solution, constitutes an infringement of the present invention's patent and will be subject to corresponding legal liability.
Claims
1. A method for automatically adjusting dose uniformity using multi-pole magnetic rod spacing control, characterized in that: include: The initial value of the ion beam current J0 was measured when the positions of the multiple magnetic poles remained unchanged. The ion beam current values were collected sequentially for every two non-interfering magnetic poles with the same magnetic rod spacing. Based on the collected data, the relationship between the response of the magnetic poles and the amplitude of the magnetic rod spacing is calculated. Assuming the increment of the magnetic rod spacing is equal to Δd, the mathematical model expression is as follows: ； in, To increase the ion beam current value of the i-th magnetic pole by a magnetic rod spacing of Δd, for The difference between J0 and a; i x i w i These are all mathematical model coefficients for the response of the i-th magnetic pole, obtained by fitting algorithm using the above mathematical model expression; Using the least squares method, based on the average value of the initial ion beam current... Solve the overdetermined equations and calculate the optimal spacing between the magnetic rods for each magnetic pole; The machine reads the calculation results, outputs the beam current value, and verifies the debugging effect.
2. The method for automatically adjusting dose uniformity using multi-pole magnetic rod spacing control according to claim 1, characterized in that: Data acquisition is accomplished by controlling the distance between magnetic rods using multiple magnetic poles, and dose uniformity is calculated with high accuracy. Data acquisition is performed in multiple iterations, which greatly improves the program's running speed and enables dynamic adjustment of ion beam dose uniformity.
3. The method for automatically adjusting dose uniformity using multi-pole magnetic rod spacing control according to claim 1, characterized in that: Data acquisition is completed using the moving Faraday bidirectional measurement mode, which saves about half the time compared to the unidirectional measurement mode.
4. The method for automatically adjusting dose uniformity using multi-pole magnetic rod spacing control according to claim 1, characterized in that: During data acquisition, the stability of the machine determines the stability and reliability of the method for automatically adjusting dose uniformity.
5. The method for automatically adjusting dose uniformity using multi-pole magnetic rod spacing control according to claim 1, characterized in that: During data acquisition, if transient interference with the ion beam or abnormal situations such as no beam occur, the method for automatically adjusting dose uniformity has filtered out abnormal data in the above-mentioned abnormal situations, ensuring data stability and program continuity.
6. The method for automatically adjusting dose uniformity using multi-pole magnetic rod spacing control according to claim 1, characterized in that: By analyzing the mathematical model expression, different initial current densities J0 correspond to different response curves. By replacing J0 with a new one during the iteration process and performing iterative calculations, the calculation speed of the method for automatically adjusting dose uniformity is further improved.