阅读说明：本技术 一种利用多磁极磁棒间距控制的自动调节剂量均一性的方法 (Method for automatically adjusting dose uniformity by utilizing multi-magnetic pole magnetic bar spacing control ) 是由 杜琴 于 2019-10-15 设计创作，主要内容包括：本发明公开了一种利用多磁极磁棒间距控制的自动调节剂量均一性的方法。该方法通过调节2n个磁极磁棒之间的距离来改变磁场分布,本方法包括：测量磁极位置未改变时离子束流初始值J-0(1),上下各n个磁极分别设置相同磁棒间距,利用移动法拉第双向测量模式采集每一磁极(可同时采集两个互相不干扰的磁极)对应的离子束流值(2),计算磁极响应与磁棒间距的幅度关系,并利用该关系式迭代计算(3),利用初始束流平均值解超定方程计算出每个磁极的最佳磁棒间距值(4),机台线上验证调试效果(5)。设计多种调节模式,根据当前束流状态选择最佳的调节模式进行剂量均一性调节。本发明涉及离子注入装置及最小二乘算法,隶属于半导体制造领域。(The invention discloses a method for automatically adjusting dose uniformity by utilizing multi-magnetic pole magnetic bar spacing control. The method changes the magnetic field distribution by adjusting the distance between 2n magnetic pole magnetic bars, and comprises the following steps: measuring initial value J of ion beam current when magnetic pole position is not changed 0 (1) The upper and lower n magnetic poles are respectively provided with the same magnetic bar spacing, and the ion beam flow value corresponding to each magnetic pole (two magnetic poles which do not interfere with each other can be simultaneously acquired) is acquired by utilizing a mobile Faraday bidirectional measurement mode (2) Calculating the amplitude relation between the magnetic pole response and the magnetic bar spacing, and using the relation to iterate calculation (3), and using the initial beam average value And (5) solving an overdetermined equation to calculate an optimal magnetic rod spacing value (4) of each magnetic pole, and verifying and debugging effects on a machine line (5). And designing a plurality of adjusting modes, and selecting the optimal adjusting mode to carry out dose uniformity adjustment according to the current beam flow state. The invention relates to an ion implantation device and a least square algorithm, belonging to the field of semiconductor manufacturing.)

1. A method for automatically adjusting dose uniformity by multi-pole magnetic bar spacing control is characterized in that: data acquisition is completed by controlling the distance between the magnetic rods through the multiple magnetic poles, the uniformity of calculated dose is high, the calculation precision is high, the data acquisition can be repeatedly calculated by iteration once, the program running speed can be greatly improved, and the dynamic adjustment of the uniformity of the ion beam dose is realized.

2. A method for automatically adjusting dose uniformity by multi-pole magnetic bar spacing control is characterized in that: the data acquisition is completed by utilizing a mobile Faraday bidirectional measurement mode, and about half of time is saved compared with a unidirectional measurement mode.

3. A method for automatically adjusting dose uniformity by multi-pole magnetic bar spacing control is characterized in that: in the data acquisition process, the stability of the machine determines the stability and reliability of the algorithm.

4. A method for automatically adjusting dose uniformity by multi-pole magnetic bar spacing control is characterized in that: in the data acquisition process, the abnormal conditions such as instantaneous interference of ion beam current or no beam current can occur, and the algorithm filters the abnormal data to ensure the stability of the data and the continuity of the program.

5. Automatic regulator utilizing multi-magnetic pole magnetic bar spacing controlA method of quantity uniformity characterized by: mathematical model for calculating and analyzing magnetic pole response curve and initial beam current J₀Assuming that the increment of the magnetic pole pitch setting is equal to Δ d, the mathematical model expression of (1) is:

whereinAndrespectively, the response current density difference and the current density at the i-th magnetic pole setting increment of deltad. a is_i、x_i、w_iAll the coefficients are response mathematical model coefficients of the ith magnetic pole, and can be obtained by a fitting algorithm. Analysis of mathematical model formula, different initial current densities J₀Corresponding to different response curves, new J can be replaced in the iterative process₀And iterative calculation is carried out, so that the calculation speed of the algorithm is further improved.

Technical Field

The invention relates to the field of semiconductor equipment manufacturing, in particular to a technology for automatically adjusting the dose uniformity of an ion beam by utilizing multi-magnetic pole magnetic bar spacing control of an ion implanter.

Background

Under the global trend, the semiconductor industry has become a critical area concerning the national strategic safety. With the development of semiconductor integrated circuit manufacturing processes, higher demands are placed on the performance of semiconductor manufacturing equipment. In a semiconductor manufacturing apparatus, an ion implanter is a doping apparatus which is a core in semiconductor device manufacturing, and is mainly used for doping processing for changing the conductivity type and voltage of a target material, when the wafer size enters 300mm, advanced device manufacturing processes are continuously advanced by 7nm and 5nm, and in order to ensure the consistency of device performance on the whole wafer, higher requirements on uniformity indexes in the ion implantation doping process are required. Therefore, it becomes important to realize automatic adjustment of the dose uniformity of the ion beam current. Based on the requirements, the invention provides a method for automatically adjusting the dose uniformity by utilizing the multi-magnetic pole magnetic rod spacing control, and the automatic adjustment of the dose uniformity of the ion beam current is realized.

Disclosure of Invention

The invention provides a novel method for automatically adjusting the dose uniformity by controlling the spacing of multi-magnetic pole magnetic bars in the prior ion implanter technology, and provides reliable and effective support for the implantation of terminal ions.

The invention is realized by the following scheme:

measuring initial value J of ion beam current when multi-magnetic pole position is not changed₀(1) (ii) a The distance between the same magnetic rods (magnetic rod spacing for short) is increased or decreased by 2n magnetic poles respectively, and the ion beam flow value corresponding to each magnetic pole is collectedAnd the response beam current values of two mutually noninterference magnetic poles can be acquired at one time, so that the moving Faraday motion times are reduced. In order to further improve the efficiency of data acquisition, the traditional motion mode of the mobile Faraday is changed from the original one-way measurement mode to the two-way measurement mode, and about half of time is saved on the original basis. In the data acquisition process, abnormal conditions such as beam current sudden interruption or no beam current and the like can occur, the abnormal data are filtered by the algorithm, and the stability of the data and the continuity of a program are ensured (2); calculating the amplitude relationship between the response of the magnetic pole and the distance between the magnetic bars according to the collected data, and assuming the magnetic poleThe rod spacing setting increment is equal to Δ d, and the mathematical model expression is as follows:

whereinAndrespectively, the response current density difference and the current density at the j-th magnetic pole setting increment of deltad. a is_i、x_i、w_iAll the coefficients are response mathematical model coefficients of the ith magnetic pole, and can be obtained by a fitting algorithm. Analysis of mathematical model formula, different initial current densities J₀Corresponding to different response curves, new J can be replaced in the iterative process₀Iterative calculation is carried out, and the calculation speed (3) of the algorithm is further improved; using least square method, according to the average value of each initial beam currentSolving an over-determined equation, and calculating an optimal magnetic rod spacing value (4) of each magnetic pole; and (5) reading the calculation result by the machine, outputting a beam value and verifying the debugging effect.

Three adjusting modes, namely a multi-magnetic pole upper adjusting mode, a multi-magnetic pole lower adjusting mode, a multi-magnetic pole full adjusting mode and the like are designed, and the optimal adjusting mode is selected according to the current beam state to carry out dose uniformity adjustment.

The invention has the following remarkable advantages:

1) the data are acquired by utilizing a mobile Faraday bidirectional measurement mode, and compared with a unidirectional mode, about half of time is saved;

2) by simultaneously acquiring 2 magnetic pole response data and performing iterative computation, the adjustment efficiency is greatly improved on the basis of ensuring the computation accuracy;

3) according to the current beam state, the adjusting method is automatically selected, the application range is wide, the adjusting force is large, and target adjustment can be quickly completed by embedding the C language program into the machine table;

drawings

To facilitate a fuller understanding of the present disclosure, reference is now made to the accompanying drawings.

Figure 1 shows a flow chart illustrating the mode of motion of a mobile faraday bidirectional measurement to which the present invention relates.

Fig. 2 shows a schematic diagram illustrating the true response curves of the poles at positions 3 and 9 for the embodiment of the present invention.

FIG. 3 shows a flowchart illustrating an algorithm for adjusting dose uniformity using multiple poles in accordance with the present invention.

Fig. 4 shows a flow chart illustrating the adjustment steps involved in the present invention.

Detailed Description

The invention will be further described with reference to specific embodiments thereof.

Referring to fig. 1, the present invention relates to a flow chart of a mobile faraday bidirectional measurement mode, which improves the speed of data acquisition in an algorithm by changing the motion mode of a mobile faraday, and designs a set of programs of the mobile faraday bidirectional measurement mode in a motion control system of the mobile faraday. The method comprises the steps of firstly entering a mobile Faraday bidirectional measurement mode (1), issuing a bidirectional measurement mode starting instruction, then issuing a mobile Faraday movement command for n times, enabling the mobile Faraday to sequentially complete forward data acquisition and reverse data acquisition, and circularly performing the step (2), and when n times of data acquisition is finished or an algorithm automatic adjustment algorithm is finished, issuing a command to quit the mobile Faraday bidirectional measurement mode (3) so as to ensure that the mobile Faraday returns to a safe position. The two-way measurement mode saves about half the time in data acquisition compared to the mobile faraday one-way measurement mode.

Referring to fig. 2, a schematic diagram of the true response curves of the magnetic bottom poles No. 3 and No. 9 according to the present invention is that the ion beam current true response curve is obtained by adding the same magnetic rod spacing (for example, Δ d ═ 2mm) to the magnetic bottom pole No. 3 (2) and the magnetic bottom pole No. 9 (1) at the same time in the embodiment, and the region (1) represents the response waveform of the magnetic bottom pole No. 9, and the response is usedGaussian model formula based on waveform curveFitting, finding the same initial ion beam current J₀The response wave curve is in linear relation with the adjustment increment, the adjustment of the algorithm takes the linear relation as a basic condition, and the area (2) represents the response wave curve of the No. 3 lower magnetic pole, and the response wave curve also meets the basic condition. And the rest magnetic poles can be obtained in the same way, and an initial coefficient matrix for adjusting the uniformity of the ion beam current is established according to the response waveform curve of the magnetic poles to the ion beam current.

Referring to FIG. 3, the algorithm of the present invention is a flow chart for measuring the ion beam current J when the magnetic pole position is unchanged₀(1) And judgment of J₀And whether the value is a normal value or not ensures the stability of the algorithm. Sequentially collecting ion beam current values of every two non-interfering magnetic poles with same magnetic bar spacingMeanwhile, each group of data is required to judge whether the data is a normal value or not, and is collected again when an abnormal condition occurs, and only is collected again from the position of the magnetic pole with the current abnormality. Calculating the amplitude relationship (3) between the magnetic pole response and the magnetic bar spacing, the first calculation beingAnd solving, wherein the calculation effect of the real data is better than that of the data processed by processing means such as fitting and the like. Subsequent iterative calculation does not need to finish data acquisition again according to a mathematical modelThe data in the iteration, i.e. the coefficient matrix, is only related to the initial value J of the ion beam current₀And the new coefficient matrix is calculated through the relational expression, the time for data acquisition in the iteration process is saved, the iteration frequency is set to be less than L times, and the new coefficient matrix can be set according to actual requirements. According to the average value of the initial value (1) of the ion beam currentSolving an overdetermined equation to calculate an optimal magnetic rod spacing value (4) of each magnetic pole, and finally reading the calculated result by the machine to move Faraday motion to output a beam current valueAnd (5) verifying the adjustment effect of the multi-magnetic pole on the beam current.

Referring to fig. 4, the adjusting step flowchart according to the present invention is summarized according to the algorithm and a large number of experimental results on the machine line, and the dose uniformity automatic adjusting flowchart is obtained. Firstly, reading a non-uniformity value Tmpsmigma (ion beam current standard deviation within an adjustable range of the current ion beam current) of the current ion beam current, judging whether the current ion beam current enters a multi-magnetic pole fine adjustment range, if not, starting a multi-magnetic pole full adjustment mode, and having large adjustment force and being capable of being quickly adjusted below a required value. When the initial value is smaller than the range, the current energy mode needs to be judged firstly, for the high-energy mode, in order to adjust more quickly and effectively, the adjustment mode on the multiple magnetic poles is adjusted in the first step, the adjustment mode under the multiple magnetic poles and the full adjustment mode of the multiple magnetic poles are sequentially carried out, adjustment is carried out at any time, if the adjustment mode reaches the target value, the adjustment is successful, the automatic adjustment program is quitted, if the adjustment mode can not reach the target value according to the adjustment flow, the adjustment mode can be freely selected for adjustment, or the automatic adjustment is quitted, and manual intervention is carried out. Because the high-energy mode beam state is relatively stable, the target value can be reached only by starting the multi-pole upper regulation mode or the lower regulation mode in most cases, and the time is saved by about half compared with the full regulation. When the beam current state is in the low-energy mode, the beam current state is divergent, the adjustment can be completed only by starting the full-adjustment mode for many times, the iteration for three times still does not reach the target value (the iteration times can be set according to the actual situation), and finally the adjustment mode can be freely selected or the automatic adjustment is quitted for manual intervention. Any one regulation mode can judge the regulation effect after completing one regulation, if the non-uniformity value after the regulation is larger than that before the regulation, the regulation is invalid, and the last group of regulation results should be returned; if the adjustment is effective, the subsequent adjustment is continued, and the detailed flow is shown in fig. 4.

The present invention has been described in detail in the foregoing. Those skilled in the art can make various changes and modifications to the disclosed methods and techniques without departing from the spirit of the present invention, and it should be understood that any simple modification, equivalent change and modification made to the above embodiments without departing from the technical spirit of the present invention will constitute an infringement of the present invention and will bear the relevant legal responsibility.