Superatom beam source screening method

Abstract

The invention belongs to the technical field of semiconductor material surface processing, and discloses a super-atom beam source screening method. The super-atom beam source screening method comprises the following steps: performing ionization treatment on a super-atom beam source, so that the super-atom beam source loses electrons and shows positive electricity to form super-atom ions and single-atom ions; applying an electric field to enable the electron-lost super-atom beam source to directionally move in an accelerated manner, and collecting the electron-lost super-atom beam source by a beam collector to form a beam; and the beam is introduced into an internal channel of a magnetic screening device for screening, and monatomic ions in the super-atomic beam source are filtered out. According to the super-atomic beam source screening method provided by the invention, the super-atomic ions and the monatomic ions have the same kinetic energy, the mass of the super-atomic ions is higher than that of the monatomic ions, the deflection radius of the high-mass super-atomic ions is very large, and the super-atomic ions are hardly influenced by a magnetic field of an internal channel, so that the super-atomic beam source can be screened through a magnetic screening device; the deflection radius of the monatomic ions with low mass is small, and the monatomic ions are more easily deflected and filtered out, so that the proportion of the superatoms in the superatom beam is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor material surface processing, and particularly to a method for screening superatom beam sources. Background Art

[0002] With the development of ultra-large scale integrated circuits, the semiconductor surface processing technology has become increasingly refined, especially in the wafer surface polishing and etching processes. In conventional plasma process treatments, gas molecules are ionized to form single-atom ions that bombard the wafer surface, which can have a significant implantation effect on the wafer surface lattice, affecting the surface smoothness and lattice quality.

[0003] A superatom is a nanoparticle with a diameter at the nanometer level formed by gas molecules bound together by van der Waals forces, which contains hundreds to thousands of gas molecules. When a superatom undergoes ionization collisions and electromagnetic field motions, it can be regarded as an "atom". However, compared with a single atom, the particle mass and collision cross-section increase by several times to thousands of times. When a superatom collides with the material surface, lateral sputtering effects and local thermal annealing effects will occur, which can effectively improve the surface smoothness and surface lattice quality. This characteristic has achieved good process effects in wafer surface treatment.

[0004] Superatom beams have shown broad application prospects in the field of high-precision processing. However, there are many problems to be solved in the formation process of superatom beams. For example, after the adiabatic expansion of gas molecules, the thermal motion decreases sharply. In the process of binding the colliding gas molecules by van der Waals forces between molecules to form superatoms, not all gas molecules can be combined to form superatoms. Those unbound gas molecules exist alone, and these alone-existing gas molecules are ionized to form single-atom ions similar to those, which will have a significant implantation effect on the wafer surface lattice when bombarding the wafer surface later, affecting the surface smoothness and lattice quality. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for screening superatom beam sources, aiming to solve the problem that in the existing superatom beams, due to the inclusion of unbound gas molecules, the alone-existing gas molecules are ionized to form single-atom ions similar to those, which bombard the wafer surface and affect the surface smoothness and lattice quality. This superatom beam source screening method can filter out single-atom ions with low mass, increase the proportion of superatoms in the superatom beam, and improve the process effect.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] A method for screening superatom beam sources includes the steps of:

[0008] Ionize the superatom beam source to make the superatom beam source lose electrons, showing a positive charge, and form superatom ions and single-atom ions;

[0009] Apply an electric field to direct and accelerate the movement of the superatom beam source that has lost electrons, and form a beam after being converged by a beam collector.

[0010] Introduce the beam into the internal channel of the magnetic screening device for screening to filter out single-atom ions in the superatom beam source.

[0011] In some possible implementation manners, the center of the internal channel has a uniform magnetic field, and the magnetic field intensity gradually increases from the center to the outside along the radial direction of the internal channel.

[0012] In some possible implementation manners, the length of the internal channel is 20 mm - 200 mm; the diameter of the internal channel is 10 mm - 80 mm.

[0013] In some possible implementation manners, the material of the internal channel is graphite, aluminum, or stainless steel.

[0014] In some possible implementation manners, the magnetic screening device includes an annular mounting plate. The annular mounting plate is sleeved outside the internal channel. A magnetic array is arranged between the annular mounting plate and the internal channel. The inner wall of the annular mounting plate forms a mounting surface. The magnetic array includes at least four magnets. The magnets have an isosceles trapezoidal structure, and the lower base of the isosceles trapezoidal structure is mounted on the mounting surface.

[0015] In some possible implementation manners, a magnetic array is arranged on the outer peripheral side of the internal channel. The magnetic array includes at least four magnets. The magnetization directions of two relatively arranged magnets are the same, and the angle of the magnetization directions of two adjacent magnets

[0016] In some possible implementation manners, the magnets are distributed to form a Halbach array; the intensity of the uniform magnetic field at the center of the internal channel is 0.05 T - 0.7 T.

[0017] In some possible implementation manners, the length of the upper base of the isosceles trapezoidal structure is 3 mm - 30 mm.

[0018] In some possible implementation manners, a cooling structure is arranged inside the annular mounting plate.

[0019] In some possible implementation manners, the magnetic array includes 12 magnets, and the angle of the magnetization directions of two adjacent magnets is 60°.

[0020] Advantages of the present invention:

[0021] The method for screening a superatom beam source provided by the present invention ionizes the superatom beam source. After the superatom beam source loses electrons, superatom ions and single-atom ions are formed. After applying an electric field, the superatom ions and single-atom ions move directionally and are accelerated. After being converged by a beam collector, a beam is formed and introduced into an internal channel. Since the superatom ions and single-atom ions have the same kinetic energy, there is only a difference in mass between them, and the mass of the superatom ions is hundreds to thousands of times that of the single-atom ions. According to the radius formula of ions moving in a circular motion in a magnetic field: The larger the ion mass, the larger the moving radius; the smaller the ion mass, the smaller the moving radius. The superatom ions with high mass have a very large deflection radius and are hardly affected by the magnetic field of the internal channel, so they can pass through the magnetic screening device. The single-atom ions with low mass have a smaller deflection radius and are more likely to deflect and be filtered out. Furthermore, the proportion of superatoms in the superatom beam can be increased, and the process effect can be improved. Description of the Drawings

[0022] Figure 1 is a schematic diagram of the method for screening a superatom beam source provided by an embodiment of the present invention;

[0023] Figure 2 is a cross-sectional view of the magnetic screening device used in the method for screening a superatom beam source provided by an embodiment of the present invention;

[0024] Figure 3 is a cross-sectional view of the assembled annular mounting plate and magnet provided by an embodiment of the present invention;

[0025] Figure 4 is a three-dimensional view of the assembled annular mounting plate, outer shell, and magnetic array provided by an embodiment of the present invention;

[0026] Figure 5 is a three-dimensional view of the annular mounting plate provided by an embodiment of the present invention;

[0027] Figure 6 is a simulation diagram of the magnetic field strength distribution of the internal channel provided by an embodiment of the present invention.

[0028] In the figure:

[0029] 100, magnetic screening device; 110, internal channel; 120, outer shell; 130, magnetic array; 131, magnet; 140, end cover; 150, support seat; 160, annular mounting plate; 200, ionization device. Detailed Embodiment

[0030] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. In addition, it should be noted that for the sake of description, only parts related to the present invention are shown in the drawings, rather than all structures.

[0031] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over", and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "under", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0033] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "right", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0034] This embodiment provides a method for screening a superatomic beam source, aiming to solve the problem that in the existing superatomic beam, due to the inclusion of unbound gas molecules, the gas molecules existing alone are ionized to form single-atom ions similar to those, which bombard the wafer surface and affect the surface smoothness and lattice quality. This method for screening a superatomic beam source can filter out single-atom ions with low mass, increase the proportion of superatoms in the superatomic beam, and improve the process effect.

[0035] See Figure 1 , the method for screening a superatomic beam source includes the following steps:

[0036] S1. Ionize the superatomic beam source to make the superatomic beam source lose electrons, showing a positive charge, and form superatomic ions and single-atom ions;

[0037] S2. Apply an electric field to make the superatomic beam source that has lost electrons move in a directed and accelerated manner, and form a beam after being converged by a beam collector;

[0038] S3. Introduce the beam into the internal channel 110 of the magnetic screening device 100 for screening to filter out the single-atom ions in the superatom beam source.

[0039] In the above superatom beam source screening method, the ionization device 200 is used to ionize the superatom beam source. After the superatom beam source loses electrons, superatom ions and single-atom ions are formed. After applying an electric field, the superatom ions and single-atom ions move directionally and are accelerated. After being converged by the beam collector, a beam is formed and introduced into the internal channel 110. Since the superatom ions and single-atom ions have the same kinetic energy, there is only a difference in mass between them, and the mass of the superatom ions is hundreds to thousands of times that of the single-atom ions. According to the radius formula when ions move in a circular motion in a magnetic field: The larger the ion mass, the larger the movement radius; the smaller the ion mass, the smaller the movement radius. The superatom ions with high mass have a very large deflection radius and are hardly affected by the magnetic field in the internal channel 110, so they can pass through the magnetic screening device 100. The single-atom ions with low mass have a smaller deflection radius and are more likely to deflect and be filtered out. Thus, the proportion of superatoms in the superatom beam can be increased, and the process effect can be improved.

[0040] Optionally, the center of the internal channel 110 has a uniform magnetic field, and the magnetic field strength gradually increases from the center to the outside along the radial direction of the internal channel 110. When the ionized superatom beam source enters the internal channel 110, under the action of the magnetic field, the single-atom ions deviate from the center of the internal channel 110 and finally deflect to the inner wall surface of the internal channel 110 and disappear, thus being screened out. See Figure 6 , Figure 6 which is a simulation diagram of the magnetic field strength distribution of the internal channel 110.

[0041] Optionally, the length of the internal channel 110 is 20 mm - 200 mm; the diameter of the internal channel 110 is 10 mm - 80 mm. This setting allows the superatom ions and single-atom ions to have sufficient movement ranges to ensure sufficient filtering of the single-atom ions.

[0042] Preferably, the material of the internal channel 110 is graphite, aluminum or stainless steel. Graphite, aluminum or stainless steel all belong to corrosion-resistant materials and meet the corrosion-resistant characteristics.

[0043] See Figures 2 to 5, in this embodiment, the magnetic screening device 100 includes an annular mounting plate 160. The annular mounting plate 160 is sleeved outside the inner channel 110. A magnetic array 130 is arranged between the annular mounting plate 160 and the inner channel 110. The inner wall of the annular mounting plate 160 forms a mounting surface. The magnetic array 130 includes at least four magnets 131. The magnets 131 are in an isosceles trapezoid structure, and the lower base of the isosceles trapezoid structure is mounted on the mounting surface. The magnetic array 130 arranged in this way makes the magnetic field intensity in the central region of the inner channel 110 the lowest, which can ensure the smooth progress of the superatom beam screening. Optionally, the lower base of the magnet 131 is adhesively bonded to the mounting surface, and the annular mounting plate 160 is riveted and fixed to the housing 120.

[0044] Furthermore, the magnetization directions of two relatively arranged magnets 131 are the same, and the angle between the magnetization directions of two adjacent magnets 131 In this way, the magnetic field intensity can be optimized, which can ensure the effective progress of the superatom beam screening. Preferably, the magnetic array 130 includes 12 magnets 131, and the angle between the magnetization directions of two adjacent magnets 131 is 60°. Optionally, the length of the magnet 131 is 20 mm - 160 mm.

[0045] Preferably, the length of the upper base of the isosceles trapezoid structure is 3 mm - 30 mm. If the length of the upper base of the isosceles trapezoid structure is larger, the magnetic field intensity in the inner channel 110 is weaker, resulting in too small a deflection angle of single atomic ions and unable to screen single atomic ions. If the length of the upper base of the isosceles trapezoid structure is smaller, the magnetic field intensity in the inner channel 110 is stronger, which will cause a large number of single atomic ions to deflect to the front part of the inner channel 110, resulting in a sharp rise in the temperature of this section of the inner channel 110. In addition, some superatomic ions with smaller masses are affected and deflected, and cannot be emitted from the emission hole of the inner channel 110, resulting in low screening efficiency.

[0046] Optionally, the uniform magnetic field intensity at the center of the inner channel 110 is 0.05 T - 0.7 T, and the magnets 131 are distributed to form a Halbach array. With such a setting, the motion trajectory of single atomic ions can be optimized, ensuring the full filtration of single atomic ions and improving the use reliability of the inner channel 110 at the same time.

[0047] In this embodiment, a cooling structure can be arranged in the annular mounting plate 160. When single atomic ions deflect to the inner channel 110, it will cause the temperature to rise. The cooling structure can play a role in cooling down and avoid the magnetic screening device 100 from being damaged by heat. Exemplarily, the cooling structure can be a cooling pipe, which is coiled in the cooling cavity of the annular mounting plate 160, and a cooling medium, such as cooling water, can be introduced into the cooling pipe.

[0048] See Figure 2, the magnetic screening device 100 further includes a housing 120 sleeved outside the annular mounting plate 160. The front end of the housing 120 (i.e., the incident end of the superatomic beam) is covered with an end cap 140 to protect the components inside the housing 120; a support base 150 for support is provided at the bottom of the housing 120; a plurality of heat sinks are provided at the rear end of the housing 120 (i.e., the outgoing end of the superatomic beam). Since the density of ion bombardment of the internal channel 110 on the side close to the outgoing end is relatively large, the temperature at this end is relatively high. By providing heat sinks, it is avoided that the temperature is too high to affect the process effect and the structure is damaged due to too high temperature.

[0049] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A superatom beam source screening method, characterized in that: Includes steps: ionizing the superatomic beam source, so that the superatomic beam source loses electrons and becomes positively charged, thereby forming superatomic ions and monatomic ions; Applying an electric field to accelerate the super-atom beam source that has lost its electrons to move in a directional manner, and to form a beam after being focused by a focusing device; The beam is introduced into an internal channel (110) of a magnetic screening device (100) for screening, thereby filtering out the monoatomic ions in the superatomic beam source.

2. The superatom beam source screening method according to claim 1, characterized in that: The center of the internal channel (110) presents a uniform magnetic field, and the magnetic field strength gradually increases from the center to the outside along the radial direction of the internal channel (110).

3. The superatom beam source screening method according to claim 1, characterized in that: The length of the internal channel (110) is 20 mm to 200 mm; the diameter of the internal channel (110) is 10 mm to 80 mm.

4. The superatom beam source screening method according to claim 1, characterized in that: The material of the internal channel (110) is graphite, aluminum or stainless steel.

5. The superatom beam source screening method according to claim 1, characterized in that: The magnetic screening device (100) comprises an annular mounting plate (160), the annular mounting plate (160) being sleeved on the outer side of the internal channel (110), a magnetic array (130) being arranged between the annular mounting plate (160) and the internal channel (110), the inner wall of the annular mounting plate (160) forming a mounting surface, the magnetic array (130) comprising at least four magnets (131), the magnets (131) being in an isosceles trapezoidal structure, the lower base of the isosceles trapezoidal structure being mounted on the mounting surface.

6. The superatom beam source screening method according to claim 5, characterized in that: A magnetic array (130) is arranged on the outer peripheral side of the internal channel (110), and the magnetic array (130) includes at least four magnets (131). The magnetization directions of two magnets (131) arranged opposite to each other are the same, and the angles of the magnetization directions of two adjacent magnets (131) are 7. The superatom beam source screening method according to claim 5, characterized in that: The magnets (131) are distributed to form a Halbach array; the uniform magnetic field strength at the center of the internal channel (110) is 0.05T-0.7T.

8. The superatom beam source screening method according to claim 5, characterized in that: The upper base length of the isosceles trapezoidal structure is 3mm-30mm.

9. The superatom beam source screening method according to claim 5, characterized in that: A cooling structure is arranged inside the annular mounting plate (160).

10. The superatom beam source screening method according to claim 6, characterized in that: The magnetic array (130) comprises 12 magnets (131), and the angle between the magnetization directions of two adjacent magnets (131) is 60°.

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