Pulse high-energy ion implanter with chopping function

Abstract

The invention discloses a pulse high-energy ion implanter with a chopping function. The pulse high-energy ion implanter comprises an ion source, a chopping unit, an analysis magnet, a radio frequency acceleration section, an energy magnet, a scanning electrode, a parallel magnet and a target chamber which are sequentially connected through a beam pipeline, the chopping unit is used for converting an ion beam entering the radio frequency acceleration section from a continuous beam to a pulse beam, and the radio frequency acceleration section comprises a radio frequency pulse power source, so that the peak power of the power source is increased while the average power of the power source is maintained, and the peak value of an acceleration electric field is improved. The device has the advantages of being compact in structure, high in stability, beneficial to improving the peak value of an accelerating electric field and the like, effectively reduces the occupied area of a machine table and meanwhile reduces the power consumption of the machine table.

Description

Technical Field

[0001] The invention relates to the technical field of ion implanters, and in particular to a pulse high-energy ion implanter with a chopping function. Background Art

[0002] Ion implantation or ion doping is an important process in chip manufacturing. Its purpose is to implant specific types of ions with specific energy into the substrate so that the substrate acquires corresponding characteristics. The equipment used to complete this process is an ion implanter. When the ion implanter is working, the required ions are generated by the ion source, and then the unnecessary impurity ions are removed by the analysis magnet (there is a certain probability that impurity ions will be produced when the ion source generates the required ions). After passing through the analysis magnet, the ions are accelerated by the acceleration device, and then the ion energy is screened by the energy magnet. Finally, they pass through the scanning electrode and the parallel magnet into the target chamber to implant the ions into the wafer.

[0003] With the development of the semiconductor industry, the energy demand for ion implantation equipment in chip manufacturers continues to increase, especially for storage devices and logic devices, higher doping ion energy is necessary. Traditional ion implanters use electrostatic accelerators, and when the ion energy requirement reaches the MeV level, the use of electrostatic accelerator structures will increase the risk of accelerator ignition and require a longer insulation distance. Therefore, when the ion energy requirement is high, radio frequency accelerators, that is, radio frequency high-energy ion implanters, are often used.

[0004] Existing continuous beam high-energy ion implanters use continuous wave RF power sources. The energy generated by RF power sources has an upper limit. Excessive power will cause problems such as overheating and sparking of power source components. Therefore, when outputting continuous wave RF signals, the acceleration voltage generated by a single power source for charged ions also has an upper limit. To achieve higher energy ion acceleration, it is necessary to set up multiple RF acceleration units on the machine, and each acceleration unit is equipped with a set of power source components. Multiple acceleration units will make the entire machine occupy a larger area, and running multiple RF acceleration units at the same time will also make the machine consume more power. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a pulsed high-energy ion implanter with a chopping function which has a compact structure, high stability and is conducive to improving the peak value of the accelerating electric field in view of the deficiencies in the prior art.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A pulsed high-energy ion implanter with a chopping function comprises an ion source, a chopping unit, an analysis magnet, a radio frequency acceleration section, an energy magnet, a scanning electrode, a parallel magnet and a target chamber which are sequentially connected through a beam pipeline; the chopping unit is used to realize the conversion of the ion beam entering the radio frequency acceleration section from a continuous beam to a pulsed beam; the radio frequency acceleration section comprises a radio frequency pulse power source to realize the increase of the peak power of the power source while maintaining the average power of the power source, thereby improving the peak value of the acceleration electric field.

[0008] As a further improvement of the present invention, the RF acceleration section further includes a plurality of RF acceleration units alternately arranged in sequence, and each RF acceleration unit corresponds to a RF pulse power source.

[0009] As a further improvement of the present invention, the chopper unit is a chopper, which includes two electrode plates arranged opposite to each other. When a pulse high voltage with opposite polarity is applied to the two electrode plates, the charged ions are deflected by the electric field and cannot enter the analysis magnet and the radio frequency acceleration section. When there is no voltage on the electrode plates, the charged ions enter the analysis magnet and the radio frequency acceleration section.

[0010] As a further improvement of the present invention, the chopping unit is a pulse electrostatic deceleration or acceleration device to achieve continuous beam shaping generated by the ion source into pulses with different energies.

[0011] As a further improvement of the present invention, the RF acceleration section also includes an adjustable delay device and a phase shifter, wherein the phase shifter is used to control the RF acceleration unit to be in an acceleration phase when the beam passes through, and the adjustable delay device is used to control the pulse acceleration electric field and the pulse beam to appear simultaneously.

[0012] As a further improvement of the present invention, the pulse width of the radio frequency pulse power source is slightly larger than the pulse width of the pulse beam, so that the beam pulse is covered by the electric field pulse.

[0013] As a further improvement of the present invention, the chopper unit is integrated inside the analysis magnet.

[0014] Compared with the prior art, the advantages of the present invention are:

[0015] The pulsed high-energy ion implanter with a chopping function of the present invention converts the ion beam entering the radio frequency acceleration section from a continuous beam to a pulsed beam by means of a pulsed chopping unit arranged after the ion source and before the analysis magnet, thereby obtaining the pulsed beam and maintaining the stability of the ion source; and a pulsed power source is used in the radio frequency acceleration section, thereby increasing the peak power of the power source while maintaining the average power of the power source, thereby achieving the establishment of an accelerating electric field with a higher amplitude in the radio frequency acceleration unit, achieving the acquisition of higher acceleration energy for charged ions in a single radio frequency acceleration unit, reducing the number of radio frequency acceleration units, reducing the floor space occupied by the entire ion implanter, and improving the final ion beam energy of the ion implanter. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structural principle of a pulsed high-energy ion implanter in a specific embodiment of the present invention;

[0017] Figure 2 A schematic diagram of the structural principle of a chopper in a specific embodiment of the present invention;

[0018] Figure 3 It is a schematic diagram of the beam being deflected by the electric field in the chopper in a specific embodiment of the present invention;

[0019] Figure 4 is a schematic diagram of a beam passing through a chopper when there is no electric field in a specific embodiment of the present invention;

[0020] Figure 5 A schematic diagram of a beam before passing through a pulse acceleration unit in a specific embodiment of the present invention;

[0021] Figure 6 A schematic diagram of a pulse acceleration voltage in a specific embodiment of the present invention;

[0022] Figure 7 It is a schematic diagram of the beam after passing through the pulse acceleration unit in a specific embodiment of the present invention;

[0023] Figure 8 A schematic diagram of the beam after passing through the analysis magnet in a specific embodiment of the present invention;

[0024] Fig. 9 This is a control logic diagram of a single radio frequency acceleration unit in a specific embodiment of the present invention;

[0025] Fig.10 A comparison diagram of the width of a power source pulse and a beam pulse in a specific embodiment of the present invention;

[0026] Legend: 1. Ion source; 2. Chopper unit; 3. Beam pipe; 4. Analysis magnet; 5. RF acceleration section; 6. Energy magnet; 7. Scanning electrode; 8. Parallel magnet; 9. Target chamber; 10. Electrode plate; 51. RF acceleration unit; 52. RF pulse power source; 53. Adjustable delay device; 54. Phase shifter. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0028] In the description of the present invention, it should be understood that the terms "side", "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0030] Example

[0031] like Figure 1 As shown, the pulsed high-energy ion implanter with chopping function of the present invention comprises an ion source 1, a chopping unit 2, an analysis magnet 4, a radio frequency acceleration section 5, an energy magnet 6, a scanning electrode 7, a parallel magnet 8 and a target chamber 9 which are sequentially connected through a beam pipe 3. The chopping unit 2 is used to realize the conversion of the ion beam entering the radio frequency acceleration section 5 from a continuous beam to a pulsed beam, and the radio frequency acceleration section 5 comprises a radio frequency pulse power source 52, so as to realize the increase of the peak power of the power source while maintaining the average power of the power source, thereby improving the peak value of the accelerating electric field.

[0032] like Figure 1 As shown, the RF acceleration section 5 further includes a plurality of RF acceleration units 51 arranged alternately in sequence, and each RF acceleration unit 51 corresponds to a RF pulse power source 52 .

[0033] In this embodiment, the traditional continuous beam ion implanter is optimized to a pulsed ion implanter, and the peak power is increased by using a pulsed power source, thereby increasing the peak electric field of the accelerating electric field, reducing the number of radio frequency acceleration units required to accelerate ions to the same energy, and reducing the machine footprint. Moreover, the ion source 1 produces a continuous beam, which has higher stability than using a pulsed ion source.

[0034] In this embodiment, the chopper unit 2 is a chopper. Figure 2 As shown, the chopper includes two electrode plates 10 arranged opposite to each other. Figure 3 As shown, when a pulse high voltage with opposite polarity is applied to the two electrode plates 10, the charged ions are deflected by the electric field and hit the tube wall, and cannot enter the analysis magnet 4 and the radio frequency acceleration section 5. Figure 4 As shown, when there is no voltage on the electrode plate 10, the charged ions move forward normally, pass through the analysis magnet 4 and enter the radio frequency acceleration section 5, so that the beam entering the radio frequency acceleration section 5 is a pulse beam.

[0035] In other embodiments, due to the presence of the analysis magnet 4 at the rear end of the chopping unit 2, a simpler "chopping" method can be used, that is, the chopping unit 2 can use a pulse electrostatic deceleration or acceleration unit to shape the continuous beam generated by the ion source 1 into pulses with different energies. Due to the energy selectivity of the analysis magnet 4, the ion beam entering the radio frequency acceleration section 5 can also be a pulsed beam. Figure 5 , Figure 6 and Figure 7 The figure shows a form of using a pulse acceleration unit. Before entering the acceleration unit, the beam is a single energy DC beam. After being accelerated by the pulse acceleration unit, the beam is shaped into a quasi-pulse beam with two energies. Figure 8 As shown, by setting the current value of the analysis magnet 4, one type of beam energy can be filtered out, so that the beam entering the radio frequency acceleration section 5 is a pulsed beam.

[0036] In this embodiment, the RF acceleration section 5 also includes an adjustable delay 54 and a phase shifter 53. Since the time for the beam to pass through each RF acceleration unit 51 is different, it is different from a continuous beam ion implanter. A pulsed ion implanter needs to consider the pulse power loading time, that is, it needs to be realized that when the beam just passes through the acceleration unit, the pulse power is fed in at the same time, so that an acceleration field is established at the pulsed acceleration unit 51. Fig. 9 The control logic of a single RF acceleration unit 51 is controlled by setting an adjustable delay 53 to control the pulse acceleration electric field and the pulse beam to appear simultaneously. It can be expected that since the beam passes through each RF acceleration unit in sequence, the setting value of the adjustable delay is also different (if the influence of the transmission cable is not considered, it should increase in sequence). The phase shifter 54 is used to control the RF acceleration unit to be in the acceleration phase when the beam passes.

[0037] like Fig.10 As shown, since there is a certain field building time when the pulse power is fed into the acceleration unit, the pulse width of the RF pulse power source 52 can be set to be slightly larger than the pulse width of the pulse beam, so that the beam pulse is covered by the electric field pulse.

[0038] Furthermore, in order to save the floor space of the machine, the chopper unit 2 can be integrated inside the analysis magnet 4. In theory, the use of a pulse magnet can also realize the pulsing of the ion beam entering the radio frequency band.

[0039] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A pulsed high-energy ion implanter with a chopping function, characterized in that: The invention comprises an ion source (1), a chopper unit (2), an analysis magnet (4), a radio frequency acceleration section (5), an energy magnet (6), a scanning electrode (7), a parallel magnet (8) and a target chamber (9) which are sequentially connected via a beam pipeline (3); the chopper unit (2) is used to realize the conversion of the ion beam entering the radio frequency acceleration section (5) from a continuous beam to a pulsed beam; the radio frequency acceleration section (5) comprises a radio frequency pulse power source (52) to realize the increase of the peak power of the power source while maintaining the average power of the power source, thereby improving the peak value of the accelerating electric field.

2. The pulse high energy ion implanter with chopping function according to claim 1, characterized in that: The radio frequency acceleration section (5) further comprises a plurality of radio frequency acceleration units (51) arranged alternately in sequence, and each radio frequency acceleration unit (51) corresponds to a radio frequency pulse power source (52).

3. The pulse high energy ion implanter with chopping function according to claim 2, characterized in that: The chopper unit (2) is a chopper, which comprises two electrode plates (10) arranged opposite to each other. When a pulsed high voltage with opposite polarities is applied to the two electrode plates (10), the charged ions are deflected by the electric field and cannot enter the analysis magnet (4) and the radio frequency acceleration section (5). When there is no voltage on the electrode plates (10), the charged ions enter the analysis magnet (4) and the radio frequency acceleration section (5).

4. The pulse high energy ion implanter with chopping function according to claim 2, characterized in that: The chopper unit (2) is a pulse electrostatic deceleration or acceleration device, which is used to shape the continuous beam generated by the ion source (1) into pulses with different energies.

5. The pulsed high energy ion implanter with chopping function according to any one of claims 2 to 4, characterized in that: The radio frequency acceleration section (5) further comprises an adjustable time delay device (54) and a phase shifter (53), wherein the phase shifter (53) is used to control the radio frequency acceleration unit (51) to be in an acceleration phase when the beam passes through, and the adjustable time delay device (54) is used to control the pulse acceleration electric field and the pulse beam to appear simultaneously.

6. The pulsed high energy ion implanter with chopping function according to any one of claims 1 to 4, characterized in that: The pulse width of the radio frequency pulse power source (52) is slightly larger than the pulse width of the pulse beam, so that the beam pulse is covered by the electric field pulse.

7. The pulse high energy ion implanter with chopping function according to any one of claims 1 to 4, characterized in that: The chopper unit (2) is integrated inside the analyzing magnet (4).

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