CN116031124A - Arcing chamber structure of ion source for ion implanter and working method thereof - Google Patents

Abstract

The invention provides an arc starting chamber structure of an ion source for an ion implanter and a working method thereof, which are suitable for the ion source of the ion implanter, wherein the ion source of the ion implanter comprises a filament component, a cathode component, a semi-cylindrical arc starting chamber component, a process gas inlet component and a reflector component; the semi-cylindrical arcing chamber component adopts a semi-cylindrical chamber design, and the reflector component adopts a suspended reflector design. The arc starting chamber structure of the ion source for the ion implanter is a semicircular arc starting chamber, so that the assembly and maintenance flow of the ion source are simplified; the invention adopts the optimized filament and cathode components, effectively prolongs the service life of the ion source and greatly improves the productivity of the ion implanter. Through brand new research and development design, the invention reduces the energy consumption of the ion source, improves the efficiency of ion extraction and the intensity of beam current, and further improves the yield of process products.

Description

Arcing chamber structure of ion source for ion implanter and working method thereof

Technical Field

The invention belongs to the technical field of semiconductor equipment, and particularly relates to an arc starting chamber structure of an ion source for an ion implanter and a working method thereof.

Background

Conventional ion sources of ion implanters have many problems in use, including 1. The ion source has a short lifetime (typically about 100 hours), and conventional ion sources often experience filament breakage, cathode breakdown, etc. at the end of the lifetime. Meanwhile, the process operation is suddenly interrupted, and unnecessary troubles such as follow-up repair and beating are required. 2. The current of the ion beam is too small to meet the technological requirements of advanced manufacturing, the traditional ion source is relatively difficult to strike an arc in the use process, and relatively large energy is required to be applied to each component of the ion source to extract a relatively small amount of ion beam. This reduces the efficiency of the entire ion implanter and thus affects the production of the product. 3. Ion beam uniformity is poor and there is a unfilled corner above the ion beam. Conventional ion sources have a significant impact on the uniformity of the ion beam and the more difficult it is to control the uniformity of the ion beam toward the end of the ion source lifetime. This further shortens the lifetime of the ion source, causing more downtime. 4. The bottom of the arcing chamber is planar such that the volume of the entire arcing chamber is relatively small and the ionization rate of the process gas is relatively low. The traditional ion source arcing chamber adopts a planar design, so that the reaction volume of the arcing chamber cannot be optimized to the greatest extent, and the process gas introduced into the arcing chamber cannot be fully ionized. Not only is a great deal of process gas wasted, but also by-products generated by a great deal of process gas introduced into the arcing chamber are attached to the surface of the ion source, thereby further reducing the service life of the ion source and the quality of the ion beam.

With the development of semiconductor process technology and the improvement of process requirements, it is significant to design and reform an ion source which has low energy consumption, low maintenance, high stability and can generate high-quality ion beams.

Disclosure of Invention

Based on the problems existing in the prior art, the invention provides an arc starting chamber structure of an ion source for an ion implanter and a working method thereof.

According to a first aspect of the present invention, the present invention provides an arcing chamber structure for an ion source of an ion implanter, which is suitable for the ion source of the ion implanter, wherein the ion source of the ion implanter comprises a filament assembly, a cathode assembly, a semi-cylindrical arcing chamber assembly, a process gas inlet assembly and a reflector assembly; the semi-cylindrical arcing chamber component adopts a semi-cylindrical chamber design, and the reflector component adopts a suspended reflector design.

Further, the filament assembly is used for heating the filament to generate free electrons, and the generated free electrons enter the cathode under the action of an electric field so as to bombard the cathode assembly. The cathode assembly generates a large number of free electrons upon receiving bombardment from the filament electrons and enters the strike chamber assembly under the influence of an electric field.

Still further, an arcing chamber structure for an ion source of an ion implanter includes a filament clamp, a cathode insulator, a filament, a refractory bolt, and a filament energy supply rod. The heat-resistant bolts fix 2 filament clamps to the outside of the cathode insulator, the filament is connected with the filament clamps, and corresponding energy is applied to the filament through the filament energy supply rod, so that the filament is heated and electrons are generated.

Preferably, the arcing chamber structure of the ion source for the ion implanter further comprises a cathode, which is inserted into the circular ring of the holder and locked by a set screw. The position of the cathode is adjusted to ensure that the fastening bolt is completely abutted against the semicircular hole on the pore canal of the filament clamp and the bolt is locked. The filament is slowly pushed into the cathode, and 2 positioning pins on the support are pressed into pin holes of the cathode insulator, so that the support and the cathode insulator are tightly attached, and no gap exists in the middle.

According to a second aspect of the present invention, there is provided a method of operating an arcing chamber structure for an ion source of an ion implanter, comprising the steps of:

step S1, heating a filament assembly to generate electrons to bombard a cathode;

step S2, a cathode assembly generates a large number of electrons to enter an arcing chamber;

step S3, introducing process gas into the arcing chamber;

step S4, free electrons collide with the reaction gas to generate plasma;

step S5, the reflector assembly reflects electrons continuously colliding with the process gas.

Compared with the prior art, the arcing chamber structure of the ion source for the ion implanter has the following beneficial technical effects:

1. the arc starting chamber structure of the ion source for the ion implanter is a semicircular arc starting chamber, so that the assembly and maintenance flow of the ion source are simplified.

2. The invention adopts the optimized filament and cathode components, effectively prolongs the service life of the ion source and greatly improves the productivity of the ion implanter.

3. Through a brand new research and development design, the invention reduces the energy consumption of the ion source, improves the efficiency of ion extraction and the intensity of beam current, and further improves the yield of process products.

Drawings

Fig. 1 is a schematic diagram of an exploded view of an arc starting chamber structure of an ion source for an ion implanter in accordance with the present invention.

Fig. 2 is a schematic structural view of a filament assembly in the strike chamber structure of the ion source for the ion implanter of fig. 1.

Fig. 3 is a schematic structural view of a cathode assembly in the arcing chamber configuration of the ion source for the ion implanter of fig. 1.

Fig. 4 is a schematic structural view of a semi-cylindrical arcing chamber assembly in the arcing chamber structure of the ion source for the ion implanter of fig. 1.

Fig. 5 is a schematic structural view of a repeller assembly in the strike chamber configuration of the ion source for the ion implanter of fig. 1.

Fig. 6 is a schematic structural view of a gas introduction assembly in the arcing chamber configuration of the ion source for the ion implanter of fig. 1.

Fig. 7 is a schematic workflow diagram of an arcing chamber configuration for an ion source of an ion implanter.

Reference numerals in the drawings illustrate:

a filament clamp 1; a cathode insulator 2; a filament 3; a cathode 4; a cathode sleeve 5; a first cathode terminal plate 6; a second cathode terminal plate 7; calibrating the balance pin 8; a cathode inner liner 9; a cathode-side separator 10; a ceramic nut 11; a reflector 12; a reflector side isolation plate 13; a repeller end plate 14, a repeller insulator 15; a reflector clip 16; a semi-cylindrical partition plate 17; an arcing chamber 18; a heat-resistant bolt 19; a cathode holder 20; a process gas inlet pipe 21; a lock bolt 22; a filament energy supply rod 23; a cathode energy supply rod 24; an arc starting chamber outer cover plate 25; an arcing chamber inner cover plate 26.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings. Embodiments of the invention and features of the embodiments may be combined with each other without conflict.

It should be noted that the terms "first," "second," and the like herein are merely used for distinguishing between different devices, modules, or units and not for limiting the order or interdependence of the functions performed by such devices, modules, or units.

It should be noted that references to "one", "a plurality" and "a plurality" in this disclosure are intended to be illustrative rather than limiting, and those skilled in the art will appreciate that "one or more" is intended to be construed as "one or more" unless the context clearly indicates otherwise.

The invention provides an arc starting chamber structure of an ion source for an ion implanter and a working method thereof, wherein the ion source provided with the arc starting chamber structure of the ion source for the ion implanter has the advantages of low energy consumption, low maintenance, high stability and capability of generating high-quality ion beams. The ion source comprises an optimized filament assembly, a cathode assembly, a semi-cylindrical arcing chamber assembly, a process gas inlet assembly, a reflector assembly and insulators for isolating the assemblies.

As shown in FIG. 2, the filament in the filament assembly in the ion source is made of larger size and more optimized materials, so that the heat resistance degree and the electron generation capacity of the filament are greatly improved. As shown in fig. 4, the semi-cylindrical arcing chamber component abandons the inherent planarization design, and adopts a brand new semi-cylindrical chamber design, so that the capacity of the reaction chamber is increased, the gas distribution is more uniform, and the gas ionization rate is effectively improved. The reflector assembly shown in fig. 5 adopts a suspended reflector design, so that the reflection efficiency is increased. As shown in fig. 6, the optimized gas inlet assembly makes the distribution of the process gas more uniform when entering the arcing chamber, the pressure distribution more reasonable, and the utilization rate of the process gas is effectively improved.

Further, the filament assembly is a source for heating the filament to generate free electrons, and the generated free electrons enter the cathode under the action of an electric field so as to bombard the cathode assembly. The cathode assembly generates a large number of free electrons upon receiving bombardment from filament electrons and enters the strike chamber assembly under the influence of an electric field. And the ingenious cathode assembly design enables the distance control of the cathode and the filament to be simpler and more reliable, so that the repetition rate and success rate of the ion source assembly process are greatly improved. And proper filament size and cathode thickness match, so that the service lives of the filament and the cathode are greatly prolonged. The semi-cylindrical arcing chamber assembly effectively increases the volume of the arcing chamber, and the ingenious semi-cylindrical design is more beneficial to the sufficient collision of process gas molecules and atoms with free electrons in the arcing chamber, so that more ions are generated. The design not only increases the ionization rate of the process gas, but also can reduce the use amount of the process gas, thereby reducing byproducts attached to the surface of the ion source, prolonging the service life of the ion source and improving the quality of the ion beam. The process gas inlet assembly optimizes the pressure distribution and uniformity of the process gas introduced into the arcing chamber, so that the ionization degree of the process gas is improved. The reflector assembly enables electrons in the arcing chamber to rebound back more effectively and timely when the electrons run near the reflector, and the electrons continue to collide with process gas in the arcing chamber to generate more ions. The insulators of the isolation assemblies provide efficient potential isolation so that the potentials between the filament, cathode and strike chamber are independent of each other and operate reliably.

As shown in fig. 1, the arc starting chamber structure of the ion source for the ion implanter of the present embodiment includes a filament clamp 1, a cathode insulator 2, a filament 3, a cathode 4, a cathode sleeve 5, a first cathode terminal plate 6, a second cathode terminal plate 7, a calibration balance pin 8, a cathode inner bushing 9, a cathode side separator 10, a ceramic nut 11, a repeller 12, a repeller side separator 13, a repeller end plate 14, a repeller insulator 15, a repeller clamp 16, a semi-cylindrical separator 17, an arc starting chamber 18, a heat-resistant bolt 19, a cathode holder 20, a process gas introduction tube 21, a lock bolt 22, a filament energy supply rod 23, a cathode energy supply rod 24, an arc starting chamber outer cover plate 25, and an arc starting chamber inner cover plate 26.

The heat-resistant bolts 19 fix the 2 filament clamps 1 to the outside of the cathode insulator 2, the filaments 3 are connected to the filament clamps 1, and corresponding energy is applied to the filaments through the filament energy supply rods 23, completing heating of the filaments and generating electrons. The cathode 4 is inserted into the circular ring of the bracket 20 and locked by the set screw 22. The position of the cathode 4 is adjusted so that the fastening bolt 22 is completely close to the semicircular hole on the hole channel of the filament clamp 1, and the bolt 22 is locked. The filament is slowly pushed into the cathode, and 2 positioning pins on the support are pressed into pin holes of the cathode insulator, so that the support and the cathode insulator are tightly attached, and no gap exists in the middle. The support and the cathode insulator are locked by bolts, and the bushing 5 is screwed onto the support, and the bushing and the cathode are coaxially pushed in during screwing. The filament clip is opened, the filament position is adjusted, and the filament 1 is pushed inwards until the filament is clung to the inner side of the cathode 2. The bolt 22 is unscrewed, the position of the cathode 2 is adjusted, the bolt 22 is moved out of the semicircular hole to the long hole, the inner sides of the filaments 1 and 2 form a distance, and the screw 22 is locked. The calibration balance pin 8 is inserted into the registration pin hole of the reflective end of the arcing chamber 18. The reflector end plate 14 is mounted to the arcing chamber and, when assembled, the dowel holes in the reflector end plate 14 align with dowel pins in the arcing chamber. The reflector insulator 15 is mounted on the arcing chamber by bolts and ceramic nuts 11, and positioning pin holes on the reflector insulator 15 are aligned with positioning pins and pressed in, so that the reflector insulator 15 is tightly attached to the end plate. The reflector clip 16 is mounted on the reflector insulator with heat resistant bolts 19. The 2 positioning pins 8 are inserted into the positioning pin holes of the arcing chamber, and pushed to the inner end in the holes during insertion, so that the cathode inner bushing 9 is pressed into the cathode inner end plate 7. And 2 positioning pin holes on the cathode inner end plate 7 are aligned with two positioning pins on the arcing chamber and are sleeved in and tightly attached to the cathode side of the arcing chamber. The 2 locating pin holes on the cathode end plate 6 are aligned with the 2 locating pins on the arcing chamber and sleeved in, and are clung to the cathode inner end plate. The two end plates on the cathode side are pressed and stabilized, a cathode side isolation plate 10 is plugged into a groove between the arcing chamber and the cathode inner end plate, a reflecting electrode side isolation plate 13 is plugged into a groove between the arcing chamber and the reflecting electrode end plate, a semi-cylindrical isolation plate 17 is installed in the arcing chamber, and round holes on the two are aligned. The reflector 12 was passed through a 0.5mm plug hole, and the reflector 12 and plug were mounted to the arcing chamber against the reflector spacer. The 0.5mm plug is removed and the distance between the repeller 12 and the strike chamber-ion source repeller separator is 0.5mm. The inner and outer cover plates 26, 25 are assembled over the arcing chamber, with the inner and outer cover plates 26, 25 aligned centrally with the arcing chamber. The process gas inlet pipe 21 is inserted into the circular hole at one side of the arcing chamber, the process gas inlet pipe 21 is rotated, the position is adjusted so that the air hole is downward, and the air pipe is inserted into the air hole of the process gas inlet pipe 21.

Wherein the filament assembly is composed of a filament clamp 1, a filament 3, a heat-resistant bolt 19 and a filament energy supply rod 23. The main function of the filament assembly is to generate an original electron source under the action of a filament power supply, so that the cathode assembly is bombarded, and the main material of the filament 3 is high-temperature-resistant tungsten.

The cathode assembly is composed of a cathode 4, a cathode sleeve 5, a first cathode terminal plate 6, a second cathode terminal plate 7, a cathode inner bushing 9, a cathode bracket 20, a locking bolt 22 and a cathode energy supply rod 24. The main function of the cathode assembly is that a large amount of electrons are generated by the cathode 4 and enter the arcing chamber after being bombarded by electrons generated by the filament assembly, and the main material of the cathode 4 is high-temperature-resistant tungsten.

The semi-cylindrical arcing chamber assembly consists of a cathode side isolation plate 10, a reflector side isolation plate 13, a semi-cylindrical isolation plate 17, an arcing chamber 18, an arcing chamber outer cover plate 25 and an arcing chamber inner cover plate 26. The semi-cylindrical arcing chamber component mainly has the function of serving as a reaction chamber for electrons generated by the cathode component and process gas introduced by the process gas introducing component, so that the process gas is ionized to generate plasma.

The process gas inlet assembly is mainly composed of a process gas inlet pipe 21 and other auxiliary components, and is mainly used for introducing the process gas to provide uniformly distributed and pressure-stable reaction gas.

The reflector assembly is composed of a reflector 12, a reflector end plate 14 and a reflector clamp 16, and is mainly used for reflecting electrons moving in the arcing chamber, so that the electrons continuously collide with the process gas in the arcing chamber, and the dissociation efficiency of the process gas is improved. The insulator isolating the components comprises: a cathode insulator 2, a calibration balance pin 8, a ceramic nut 11 and a repeller insulator 15. Its main function is to isolate the different electrical potentials applied between the different components.

When the ion source with the arc starting chamber structure for the ion source of the ion implanter operates, electrons generated by heating the filament are converged on the cathode 4 under the action of an electric field and bombard the cathode, so that the cathode is heated and a large number of electrons are generated, and a large number of electrons enter the arc starting chamber 18 under the action of the electric field. When the reaction gas enters the arcing chamber through the gas inlet pipeline 21, a large number of electrons generated by the cathode collide with the introduced process gas under the action of an electric field, so that the outermost valence electrons of the process gas are peeled off to form corresponding charged ions. Thus, the energy required to exfoliate the outer valence electrons of different elements is different, and the rule generally followed is that the higher the energy required to exfoliate an element of smaller relative atomic mass. This is because the closer the outer valence electrons are to the nucleus, the more energy is required to free the outer valence electrons from the confinement of the nucleus.

The ion source requires a large number of free electrons in order to transfer sufficient energy to the process gas atoms or molecules that are introduced into the arcing chamber. These free electrons are accelerated by the electrostatic potential, the accelerated free electrons strike and transfer energy to the corresponding process gas atoms or molecules, and only a small fraction of the energy (acceleration of about 1/5 to 1/10) is transferred to the dopant target. Meanwhile, in order to increase the probability of collision of free electrons with process gas atoms or molecules in the arcing chamber, the reflector 12 in this embodiment plays a role of forming a corresponding negative potential by accumulating a certain amount of electrons on the surface of the reflector, so as to repel the free electrons and enable a large amount of free electrons to be reflected back to the arcing chamber to continuously collide with the process gas atoms or molecules in the arcing chamber, so as to form more target ions.

The working steps of the arcing chamber structure of the ion source for the ion implanter are as follows:

step S1, heating a filament assembly to generate electrons to bombard a cathode;

step S2, a cathode assembly generates a large number of electrons to enter an arcing chamber;

step S3, introducing process gas into the arcing chamber;

step S4, free electrons collide with the reaction gas to generate plasma;

step S5, the reflector assembly reflects electrons continuously colliding with the process gas.

Compared with the prior art, the invention adopts the integrated arcing chamber, designs the corresponding internal protection layer, increases the working reliability of the ion source and simultaneously ensures that the ion source is easier to assemble and maintain. In addition, the optimized design of the process gas inlet pipe effectively controls the pressure and uniformity of the process gas entering the arcing chamber, and aims to increase the ionization rate of the process gas, increase the number of ions extracted from the ion source and further increase the process productivity. In addition, the embodiment adopts the optimally designed filament, and the material and the size of the filament are improved to a certain extent, so that the service life of the filament is greatly prolonged. The cathode installation and fixing device after upgrading ensures that the stability and the service life of the cathode are improved greatly.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (8)

1. An arc starting chamber structure of an ion source for an ion implanter is characterized in that the arc starting chamber structure is suitable for the ion source of the ion implanter, and the ion source of the ion implanter comprises a filament assembly, a cathode assembly, a semi-cylindrical arc starting chamber assembly, a process gas inlet assembly and a reflector assembly;

the semi-cylindrical arcing chamber component adopts a semi-cylindrical chamber design, and the reflector component adopts a suspended reflector design.

2. The arc starting chamber structure of claim 1 wherein the filament assembly is configured to heat the filament to generate free electrons, the free electrons generated entering the cathode under the influence of an electric field to bombard the cathode assembly.

3. The arc starting chamber structure for an ion source of claim 2 wherein the cathode assembly generates a plurality of free electrons upon receiving bombardment from filament electrons and enters the arc starting chamber assembly under the influence of an electric field.

4. The arc starting chamber structure of an ion source for an ion implanter according to claim 3, wherein the arc starting chamber structure of the ion source for an ion implanter comprises a filament clamp, a cathode insulator, a filament, a heat resistant bolt, and a filament energy supply rod.

5. The arc starting chamber structure of an ion source for an ion implanter according to claim 4, wherein the heat-resistant bolts fix 2 filament clamps to the outside of the cathode insulator, the filament is connected to the filament clamps, and corresponding energy is applied to the filament through a filament energy supply rod, thereby completing heating of the filament and generating electrons.

6. The arc starting chamber structure for an ion source of an ion implanter of claim 5, further comprising a cathode inserted into the annular ring of the bracket and locked with a set screw. The position of the cathode is adjusted to ensure that the fastening bolt is completely abutted against the semicircular hole on the pore canal of the filament clamp and the bolt is locked.

7. The arc starting chamber structure of claim 6, wherein the filament is slowly pushed into the cathode, and 2 positioning pins on the support are pressed into pin holes of the cathode insulator, so that the support and the cathode insulator are tightly attached without a gap therebetween.

8. A method of operating an arcing chamber arrangement for an ion source of an ion implanter, comprising the steps of:

step S1, heating a filament assembly to generate electrons to bombard a cathode;

step S2, a cathode assembly generates a large number of electrons to enter an arcing chamber;

step S3, introducing process gas into the arcing chamber;

step S4, free electrons collide with the reaction gas to generate plasma;

step S5, the reflector assembly reflects electrons continuously colliding with the process gas.

Images