Disclosure of Invention
The invention discloses a beam brake and centering unit integrated focusing ion beam micro-nano processing system, which is characterized in that a beam brake unit is arranged on the lower side of the focusing ion beam micro-nano processing system, a beam brake unit is arranged on the upper side of the focusing ion beam micro-nano processing system, and a focusing ion beam lens barrel is arranged on the upper side of the focusing ion beam micro-nano processing system.
The technical scheme adopted by the application is as follows:
[1] A beam lock and centering unit integrated focused ion beam micro-nano processing system, which comprises a first centering unit, a second centering unit, a Faraday cup and a control unit,
The control unit is respectively and electrically connected with the first centering unit and the second centering unit and is used for controlling the first centering unit and the second centering unit to form a deflection electric field;
The first centering unit and the second centering unit are arranged in the direction perpendicular to the central axis of the focused ion beam micro-nano processing system and are radially and orthogonally arranged,
The second centering unit is arranged below the first centering unit, the Faraday cup is arranged below the second centering unit,
The first centering unit is controlled to apply a first acting force for generating micron-scale displacement in a corresponding radial direction to the ion beam or cancel the applied first acting force;
The second centering unit is controlled to apply a second force for generating a micrometer-scale displacement in a corresponding radial direction to the ion beam, a third force for deviating the ion beam from an aperture of the faraday cup to block propagation of the ion beam, or cancel the applied force.
[2] The focused ion beam micro-nano processing system with integrated beam gate and centering unit according to [1], characterized in that,
The control unit is used for controlling the first centering unit to form a first deflection electric field, the first deflection electric field is used for applying the first acting force to the ion beam,
The control unit is used for controlling the second centering unit to form a second deflection electric field, the second deflection electric field is used for applying the second acting force to the ion beam,
The control unit is configured to control the second centering unit to form a third deflection electric field, where the third deflection electric field is configured to apply the third acting force to the ion beam.
[3] The focused ion beam micro-nano processing system with integrated beam gate and centering unit according to [1], wherein the first centering unit and the second centering unit have the same structure and comprise a shell, two fan-shaped electrode plates, an insulating ceramic ring, an insulating ceramic plate and a fixing plate,
The electrode plates are assembled on the insulating ceramic ring through clearance fit and are axially positioned through the wiring nails;
the insulating ceramic ring is arranged in the shell through clearance fit and positioned through a wiring nail;
The fixing piece is fixed at the upper end and the lower end of the first centering unit or the second centering unit through interference fit, the end face of the fixing piece is flush with the end face of the shell, and the fixing piece is used for limiting the axial freedom degrees of the electrode piece, the insulating ceramic ring (103) and the insulating ceramic piece.
[4] The focused ion beam micro-nano processing system with integrated beam gate and centering unit according to the step [1], which comprises a condenser (1), a movable diaphragm (2), the first centering unit (3), the second centering unit (4), a Faraday cup (5) and an objective lens (6) which are sequentially configured from top to bottom.
[5] A method for controlling an ion beam, comprising using the focused ion beam micro-nano processing system of any one of [1] to [4] with an integrated beam gate and centering unit, and
Forming a first deflection electric field by the first centering unit by using a control unit, applying the first acting force to the ion beam to generate micron-scale displacement of the ion beam in the corresponding radial direction, and
And utilizing the control unit to enable the second centering unit to form a second deflection electric field, and applying the second acting force to the ion beam to enable the ion beam to generate micron-scale displacement in the corresponding radial direction.
[6] A method for controlling an ion beam, comprising using the focused ion beam micro-nano processing system of any one of [1] to [4] with an integrated beam gate and centering unit, and
The electric field formed by the second centering unit is changed from a second deflection electric field to a third deflection electric field by the control unit, so that the acting force applied to the ion beam is changed from the second acting force to the third acting force, and the ion beam is deviated from the central axis to block the propagation of the ion beam.
[7] The method for controlling a focused ion beam micro-nano processing system integrated with a beam lock and a centering unit according to [6], wherein,
The first centering unit is controlled by the control unit to form a first deflection electric field, and the ion beam is applied with the first acting force.
[8] A method for controlling an ion beam, comprising using the focused ion beam micro-nano processing system of any one of [1] to [4] with an integrated beam gate and centering unit, and
The electric field formed by the second centering unit is changed from a third deflection electric field to a second deflection electric field by the control unit, so that the acting force applied to the ion beam is changed from the third acting force to the second acting force, the ion beam is changed from a state of deviating from the central axis to a state of generating micron-order displacement in the corresponding axial direction, and the ion beam is propagated along the central axis.
[9] The method for controlling a focused ion beam micro-nano processing system integrated with a beam gate and a centering unit according to [8], wherein the first centering unit is controlled by the control unit to form a first deflection electric field, and the ion beam is applied with the first acting force.
The beam brake and centering unit integrated focused ion beam micro-nano processing system utilizes the superposition of electric signals, and the centering unit positioned below is used as the beam brake, so that the integration of the beam brake and the centering unit is realized, the rapid closing of the ion beam under high-voltage driving and the high-precision centering shaft of the ion beam under low-voltage driving can be realized in the same unit, and the complexity of the ion optical system and circuit control is reduced. Therefore, the focused ion beam micro-nano processing system has more compact structure and more convenient assembly.
The ion beam control method can quickly realize the quick closing and starting of the ion beam and can improve the quality of processing by using the ion beam.
Detailed Description
In order that those skilled in the art will better understand the present application, a technical solution in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present application without making any inventive effort, shall fall within the scope of the present application.
Further details will be described below in connection with the drawings and examples.
One embodiment of the beam gate and centering unit integrated focused ion beam micro-nano processing system comprises a first centering unit, a second centering unit and a control unit,
The control unit is respectively and electrically connected with the first centering unit and the second centering unit and is used for controlling the first centering unit and the second centering unit to form a deflection electric field;
the first centering unit and the second centering unit are arranged in the direction perpendicular to the central axis of the focused ion beam micro-nano processing system and are arranged in a radial orthogonal mode, the second centering unit is arranged below the first centering unit,
The first centering unit is controlled to apply or cancel the first acting force for generating the micron-scale displacement in the corresponding radial direction to the ion beam;
the second centering unit is controlled to apply a second force for generating a micrometer-scale displacement in a corresponding radial direction to the ion beam, a third force for deflecting the ion beam to block propagation of the ion beam, or cancel the application of the force.
As shown in fig. 1, the beam shutter and centering unit integrated focused ion beam micro-nano processing system of one embodiment includes a condenser lens 1, a movable diaphragm 2, a first centering unit 3, a second centering unit 4, a faraday cup 5, and an objective lens 6, which are disposed in this order from top to bottom. The first centering unit 3 and the second centering unit 4 are arranged in radial orthogonal manner, that is, if the axial direction from top to bottom is the Z direction, the first centering unit 3 is located in the Y direction perpendicular to the Z direction, the second centering unit 4 is located in the X direction perpendicular to the Z direction, and the Y direction and the X direction are also 90 degrees to each other.
The condenser lens 1, the movable diaphragm 2, the faraday cup 5, and the objective lens 6 are not particularly limited, and those commonly used in the art can be employed.
The beam lock and centering unit integrated focused ion beam micro-nano processing system further comprises a control unit (not shown), wherein the control unit is electrically connected with the first centering unit 3 and the second centering unit 4 respectively and is used for controlling the first centering unit and the second centering unit to form a deflection electric field.
In the beam lock and centering unit integrated focused ion beam micro-nano processing system of one embodiment, the control unit is configured to control the first centering unit 3 to form a first deflection electric field, the first deflection electric field is configured to apply the first force to the ion beam, the control unit is further configured to control the second centering unit 4 to form a second deflection electric field, the second deflection electric field is configured to apply the second force to the ion beam, and the control unit is further configured to control the second centering unit 4 to form a third deflection electric field, the third deflection electric field is configured to apply the third force to the ion beam.
In the beam lock and centering unit integrated focused ion beam micro-nano processing system of one embodiment, as shown in fig. 2, the first centering unit 3 includes a housing 101, a pair of electrode plates 102, an insulating ceramic ring 103, two insulating ceramic plates 104, two wire nails 105, two fixing plates 106, and two wire nail gaskets 107. In addition, the first centering unit 3 and the second centering unit 4 may be assembled as one body.
In the beam lock and centering unit integrated focused ion beam micro-nano processing system of one embodiment, the electrode plates 102 may be fan-shaped, and are precisely assembled on the insulating ceramic rings 103 through clearance fit, and axial positioning is achieved by means of the wire pins 105, the insulating ceramic rings 103 are installed in the housing 101 in a clearance fit manner, and the two insulating ceramic rings 103 are also positioned by the wire pins 105 to ensure concentricity. In addition, insulating ceramic sheets 104 are mounted on the upper and lower ends of the centering unit, and they are assembled with the housing 101 by clearance fit. The two fixing sheets 106 are respectively arranged at the upper and lower ports of the centering unit, and are connected with the shell 101 by interference fit to provide firm constraint and accurate center positioning, and the end surfaces of the fixing sheets 106 are flush with the end surfaces of the shell 101, so that the degree of freedom of the electrode sheets 102, the insulating ceramic rings 103 and the insulating ceramic sheets 104 in the axial direction is effectively limited, and the rigidity and the stability of the overall structure are ensured. Fig. 4 illustrates a cross-sectional view of a first centering unit used in a beam lock and centering unit integrated focused ion beam micro-nano machining system of one embodiment.
The second centering unit 4 has the same structure as the first centering unit 3, and therefore, the structures shown in fig. 2 to 4 described above may be employed.
As described above, the first centering unit 3 and the second centering unit 4 are arranged radially orthogonally in the focused ion beam micro-nano processing system, and fig. 5 shows a cross-sectional view of the first centering unit 3 and the second centering unit 4 thus arranged.
[ Method of controlling ion Beam ]
In some embodiments of the ion beam control method, the beam lock and the centering unit integrated focused ion beam micro-nano processing system is used,
Forming a first deflection electric field by the control unit to the first centering unit 3, applying the first force to the ion beam to generate micron-scale displacement of the ion beam in the corresponding radial direction, and
The control unit is used for enabling the second centering unit 4 to form a second deflection electric field, and the second acting force is applied to the ion beam, so that the ion beam generates micron-scale displacement in the corresponding radial direction.
In the case of processing by the aforementioned focused ion beam micro-nano processing system, the ion beam is transmitted from top to bottom in the axial direction, first passes through the condenser lens 1, the movable diaphragm 2, then passes through the first centering unit 3, the second centering unit 4, the faraday cup 5, and the objective lens 6, and finally reaches the sample surface placed on the sample stage, and processes the sample.
In the above-described processing, the following control method may be employed. That is, a first deflection electric field is applied to the first centering unit 3 by the control unit, the first deflection electric field applies a first force to the ion beam so that the ion beam passing through the first centering unit 3 is displaced in the micrometer-scale with respect to the passing front direction Y to be closer to the center axis, and a second deflection electric field is applied to the second centering unit 4 by the control unit, the second deflection electric field applies a second force to the ion beam so that the ion beam passing through the second centering unit 4 is displaced in the micrometer-scale with respect to the passing front direction X to be closer to the center axis. In this case, the first centering unit 3 and the second centering unit 4 are both units that perform centering, and the ion beam is thereby brought closer to the central axis in the Y direction and the X direction, respectively.
Fig. 6 is a schematic explanatory diagram of the first centering unit for centering function. As shown in fig. 6, a is the interval distance between two electrode plates of the centering unit, b is the length of the electrode plates in the axial direction, and c1 is the distance from the lower end face of the first centering unit plate to the upper end face of the beam stop. In the case where the first deflection electric field or the second deflection electric field is formed between the 2 electrode plates of the centering unit, the first deflection electric field or the second deflection electric field functions to bring the ion beam closer to the center axis, and thus the electric field strength is relatively weak. The ion beam is deflected by the first deflection electric field or the second deflection electric field, and is displaced d1 in the radial direction, and the ion beam originally deviated from the central axis is made to approach the central axis by applying the first deflection electric field or the second deflection electric field.
The magnitudes of the displacement in the Y direction and the displacement in the X direction d1 can be set as needed.
The control unit may be used to adjust the magnitude of the aforementioned first force and thus the magnitude of displacement of the ion beam in the Y direction. The displacement may be in the order of micrometers, for example, 1 to 50 micrometers.
The control unit may be used to adjust the magnitude of the aforementioned second force and thus the magnitude of displacement of the ion beam in the X-direction. The displacement may be in the order of micrometers, for example, 1 to 50 micrometers.
In the course of the foregoing processing, it is sometimes necessary to turn off the ion beam, and the following control method may be employed. That is, the electric field formed by the second centering unit 4 is changed from the second deflecting electric field to the third deflecting electric field by the control unit, so that the force applied to the ion beam is changed from the second force to the third force, and the ion beam is deviated from the central axis to block the ion beam propagation. The aforementioned second action force is to cause the ion beam to displace in the X-direction in the micrometer scale so as to be closer to the central axis, and the aforementioned third action force is to cause the ion beam to deviate from the central axis. Thus, the third force is greater than the second force. The force applied to the ion beam may be changed from the second force to the third force by applying a voltage higher than a voltage required to generate the second force to the second centering unit 4 by the control unit, the electric field formed by the second centering unit 4 being changed from the second deflection electric field to the third deflection electric field. By the aforementioned control method, the second centering unit 4 is changed from a unit that functions as a centering unit to a unit that functions as a beam brake.
Fig. 7 is a schematic diagram illustrating the function of the second centering unit as a beam brake. As shown in fig. 7, a is a distance between two electrode plates of the second centering unit, b is a length of the electrode plates in the axial direction, and c2 is a distance from a lower end face of the second centering unit plate to an upper end face of the beam stop. When a third deflecting electric field is formed between the 2 electrode plates of the second centering unit, the ion beam is deflected from the central axis by the third deflecting electric field, and is displaced in the radial direction d2, and the ion beam originally positioned on the central axis is deflected by the application of the third deflecting electric field, and is displaced in the radial direction d2, so that the ion beam is deflected from the aperture of the faraday cup 5.
In the case of the aforementioned shut-off of the ion beam, the first centering unit 3 is controlled by the control unit to form a first deflecting electric field, thereby exerting a first force on the ion beam.
At the end of the aforementioned off-beam state, the system is required to switch the ion beam on to the process state. In this case, a control method may be employed in which the electric field formed by the second centering unit 4 is changed from the third deflection electric field to the second deflection electric field by the control unit, so that the force applied to the ion beam is changed from the third force to the second force, and the ion beam is changed from a state deviated from the central axis to a state in which a micrometer-scale displacement is generated in the X direction, so that the ion beam propagates along the central axis. Since the aforementioned third acting force is larger than the aforementioned second acting force, the acting force applied to the ion beam can be changed from the third acting force to the second acting force by applying a voltage lower than the voltage required to generate the third acting force to the second centering unit 4 by the control unit, the electric field formed by the second centering unit 4 being changed from the third deflecting electric field to the second deflecting electric field. By the aforementioned control method, the second centering unit 4 is changed from a unit that functions as a beam lock to a unit that functions as a centering.
In the aforementioned control method of switching to processing, the first centering unit 3 is controlled by the control unit to form a first deflecting electric field, thereby applying a first force to the ion beam.
In order to evaluate the centering accuracy and the ion beam closing response time of the focused ion beam micro-nano processing system, whether the system performance accords with the design index is confirmed, the optimal conditions under different voltages are calculated, each parameter of the first centering unit and each parameter of the second centering unit are respectively recorded, the results are shown in tables 1-3, wherein the response time does not consider the real-time performance of the control system, the ion beam characteristics, the signal transmission path and the like, and only the response time of the driving circuit is calculated.
Wherein the beam deflection can be calculated according to the following formula:
d=U·b(b/2+c)/Ua/a (1)
wherein a is the distance between the polar plates, b is the length of the polar plates, c is the distance from the lower end face of the polar plates to the upper end face of the beam brake diaphragm, and d is the beam deflection.
TABLE 1 Beam deflection in Y-direction vs. Voltage for first centering Unit as centering Unit
| Polar plate voltage/V | Beam deflection/mm | Response time/ns |
| 10 | 0.180 | 0.2 |
| 20 | 0.359 | 0.4 |
| 30 | 0.539 | 0.6 |
| 40 | 0.718 | 0.8 |
| 50 | 0.898 | 1.0 |
TABLE 2 Beam deflection in the X-direction vs. Voltage for the second centering Unit as a centering Unit
| Polar plate voltage/V | Beam deflection/mm | Response time/ns |
| 10 | 0.158 | 0.2 |
| 20 | 0.316 | 0.4 |
| 30 | 0.473 | 0.6 |
| 40 | 0.631 | 0.8 |
| 50 | 0.789 | 1.0 |
TABLE 3 Beam deflection and Voltage when the second centering Unit acts as a Beam brake
| Polar plate voltage/V | Beam deflection/mm | Response time/ns |
| 50 | 0.789 | 1.0 |
| 75 | 1.020 | 1.5 |
| 100 | 1.578 | 2.0 |
| 125 | 1.701 | 2.5 |
| 150 | 2.041 | 3.0 |
| 175 | 2.381 | 3.5 |
| 200 | 2.721 | 4.0 |
According to tables 1-3, the deflection of the ion beam is in nonlinear positive correlation with the electrode plate driving voltage, a dual-mode cooperative mechanism of high-voltage rapid cutting-off and micro-voltage fine centering is realized, when the second centering unit acts as a beam gate, the electrode plate of the second centering unit is applied with about 200V of high voltage, the rapid cutting-off of the ion beam can be realized, and when the first centering unit and the second centering unit exert centering action, the high-sensitivity regulation and control characteristic of 0.0158mm/V is shown when the voltage in the range below 50V is applied, and the accurate axis combination can be realized.
The present disclosure is not limited to the above-described embodiments, and it will be apparent to those skilled in the art that several modifications and variations can be made without departing from the principles of the present disclosure, and such modifications and variations are also considered to be within the scope of the present disclosure. What is not described in detail in this specification is prior art known to those skilled in the art.
The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.