CN214012896U

CN214012896U - Novel ion source plasma neutralizer

Info

Publication number: CN214012896U
Application number: CN202023146316.1U
Authority: CN
Inventors: 李伟
Original assignee: Changsha Yuanrong Technology Co ltd
Current assignee: Changsha Yuanrong Technology Co ltd
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2021-08-20
Anticipated expiration: 2030-12-23

Abstract

The utility model relates to an ion source technical field provides a novel ion source plasma neutralizer, draw the dish, set up the cooling cylinder in the cathode cylinder outside including cathode cylinder, positive pole, the cooling cylinder outside cover is equipped with the permanent magnetism magnetic ring, and there is the interval in the one end that the dish was drawn to the positive pole and the cathode cylinder, and the other end of cathode cylinder is the inlet end, is provided with the cooling cavity on the cooling cylinder and reaches and export with the import and the export of cooling cavity intercommunication, and the positive pole is drawn to the dish and is connect positive electricity, and the cathode cylinder connects negative electricity. Through the technical scheme, the problems that the plasma neutralizer is high in cost and electrons of the ion source filament type neutralizer are unstable, the continuous working time is short and pollution is caused in the prior art are solved.

Description

Novel ion source plasma neutralizer

Technical Field

The utility model relates to an ion source technical field, it is specific, relate to a novel ion source plasma neutralizer.

Background

The ion source is widely applied to the semiconductor industry and is a core component of ion cleaning equipment, ion beam sputtering equipment, ion beam etching equipment and vacuum coating equipment. The ion source is used for ionizing a specific process gas to generate plasma, accelerating and pulling out ions and bombarding a substrate to be processed. The ion source neutralizer emits electrons outwards, and generally has two functions: one is to provide initial electrons to assist the ion source in generating plasma (ion source ignition process); the other is to neutralize the positive charge accumulated on the surface of the substrate to be processed after being bombarded by ions, so that the substrate presents electric neutrality and the substrate is prevented from discharging.

In the prior art, according to the working principle, the ion source neutralizer mainly has two types:

one is to energize with a high temperature resistant wire (e.g., tungsten wire) that releases electrons in the incandescent state. The advantages of such a neutralizer are that it is cheap, simple and reliable. The disadvantages are that: short continuous service life (generally no more than 10 hours); the tungsten filament is evaporated at high temperature to form pollution; as the tungsten wire is evaporated and thinned, the amount of emitted electrons is changed, which causes process instability. This type of neutralizer is widely used in medium and low end ion sources, and is often used in hall sources and kaufman sources.

Another method is to generate plasma and pull out the electrons generated therein to emit them in a specific direction. The advantages of this approach are: long continuous working time (more than 100 hours); no pollution is caused; the amount of emitted electrons is stable. The disadvantages are that: the cost is high. The existing plasma neutralizer basically adopts a radio frequency excitation method to generate plasma, and then adopts direct current to pull out electrons to emit in a specific direction. Therefore, the neutralizer needs a radio frequency power supply and a direct current power supply, and as is well known, the price of the radio frequency power supply is high, so the price of the neutralizer is naturally high. Although expensive, all high-end ion sources in foreign countries currently employ this type of neutralizer because of the outstanding advantages of this type of ion source. In view of the above problems, there is a need for an electronic generator that is low in cost and has good stability.

SUMMERY OF THE UTILITY MODEL

The utility model provides a novel ion source plasma neutralizer has the advantage of present foreign high-end plasma neutralizer, has replaced radio frequency power supply with DC power supply simultaneously and has produced plasma to reduce cost by a wide margin has solved among the prior art plasma neutralizer with high costs and ion source filament type electron and has taken place unstability, continuous operation time weak point, has polluted problem.

The technical scheme of the utility model as follows:

the utility model provides a novel ion source plasma neutralizer, draws dish, setting including a cathode section of thick bamboo, positive pole and is in the cooling cylinder in the cathode section of thick bamboo outside, the cooling cylinder outside cover is equipped with the permanent magnetism magnetic ring, the positive pole draw the dish with there is the interval in the one end of a cathode section of thick bamboo, the other end of a cathode section of thick bamboo is the inlet end, be provided with on the cooling cylinder cooling cavity and with import and export of cooling cavity intercommunication, the positive pole draws the dish and connects positive electricity, the cathode section of thick bamboo connects the negative electricity.

And coolant is introduced into the cooling cavity.

The anode lead disc is positively charged by 30-50V.

The cathode cylinder is connected with negative electricity of 200-400V.

Add insulating ceramic ring, ceramic upper cover and stainless steel lower cover, the ceramic upper cover sets up the one end of a negative pole section of thick bamboo is located a negative pole section of thick bamboo with between the positive pole draws the dish, insulating ceramic ring with the stainless steel lower cover is followed the axial of a negative pole section of thick bamboo sets gradually the other end of a negative pole section of thick bamboo.

An air inlet is arranged on the stainless steel lower cover.

And the ceramic upper cover and the anode leading disc are both provided with electron emergent holes.

The inlet is arranged at one end far away from the anode lead disc, and the outlet is arranged at the other end of the cooling cylinder.

The utility model discloses a theory of operation and beneficial effect do:

in the prior art, argon gas is firstly introduced into a plasma chamber (made of ceramic or quartz glass), then radio frequency electricity of 13.56MHz is introduced into a water-cooling coil at the outer side of the plasma chamber, and a high-frequency alternating electromagnetic field generated by the RF coil penetrates through a cylindrical collecting electrode tightly attached to the inner side of the plasma chamber, so that the gas is ionized to generate plasma. Meanwhile, the radio frequency coil induces radio frequency voltage on the surface of the collecting electrode, an electron sheath layer is generated on the inner side of the collecting electrode to form radio frequency bias of negative voltage, ions move towards the collecting electrode under the action of negative bias, the maintaining electrode is positively charged, electrons move towards the direction of the maintaining electrode under the attraction of positive voltage of the maintaining electrode, and most of electrons are emitted through an electron emission hole in the center of the maintaining electrode to form electron beam current.

The utility model discloses a novel ion source plasma neutralizer, which mainly comprises a cathode cylinder, a cooling cylinder outside the cathode cylinder, a permanent magnet ring outside the cooling cylinder, a stainless steel lower cover at one end of the cathode cylinder, a ceramic upper cover at the other end of the cathode cylinder, and an anode leading disc (namely a maintaining electrode), wherein an interval exists between the cathode cylinder and the anode leading disc, an electric field is formed between the cathode cylinder and the anode leading disc; the inlet and the outlet of the cooling jacket are communicated with a cooling medium to form circulating cooling so as to protect the permanent magnet ring on the outer side of the cooling jacket from high-temperature demagnetization; gas (argon gas is commonly used) is introduced into the center of the stainless steel lower cover of the cathode cylinder, the argon gas is ionized into plasma under the combined action of a magnetic field formed by the permanent magnet ring in the cathode sleeve and an electric field formed by negative voltage of the cathode cylinder, the plasma is kept in the cathode cylinder, electrons move towards the direction of the anode lead plate under the action of the electric field formed by positive voltage of the anode lead plate, and partial electrons are emitted from the electron emission holes to form electron beam current. The ions in the plasma move to the wall of the cathode cylinder under the action of the electric field, and the ions absorb the charges carried by the ions. Meanwhile, the wall of the cathode barrel is bombarded by ions to form sputtering of the material of the cathode barrel, but because the cathode barrel is cylindrical, the material sputtered from the inside can be deposited on the opposite side, so that the wall of the cathode barrel can be sputtered and deposited at the same time, and the service life of the cathode barrel is long. Meanwhile, the material sputtered out of the inner part of the chamber moves linearly and is difficult to be emitted out of the electron emission hole, so that the substrate is not polluted, and the cleanliness of the process chamber is ensured;

in the working process, argon is introduced into the inner side of the cathode cylinder in the first step, negative electricity is added to the cathode cylinder in the second step, the argon is ionized under the combined action of an electric field formed by negative voltage of the cathode cylinder and a magnetic field generated by the permanent magnet ring, stable plasma is formed in the cathode cylinder, positive voltage is added to the anode lead disc in the third step, electrons move to the anode lead disc under the action of an electric field of the anode lead disc, and partial electrons are emitted through electron emission holes in the centers of the ceramic upper cover and the anode lead disc to form electron beam current.

Compared with the prior art: in the prior art, argon is introduced into a plasma chamber to ionize the argon to form plasma, or high-frequency radio frequency or microwave is used for excitation, for example, 13.56MHz radio frequency electricity is introduced to a coil outside the plasma chamber, a radio frequency coil applies a radio frequency electric field to a cylindrical collecting electrode in the plasma chamber, a radio frequency bias is formed on the surface of the collecting electrode to ionize the gas, ions approach the collecting electrode, electrons are emitted under the action of a maintaining electrode, the cost of forming an electron jet is high, the maintenance cost is also high after a fault, or high-voltage direct current (>2000 v) is used for excitation to generate plasma, and the density of the plasma generated in the mode is lower by one order of magnitude than that of the plasma generated by the radio frequency coil. The utility model discloses an add the permanent magnet in the cathode cylinder outside, form a magnetic field in cathode cylinder inboard (plasma region), similar with direct current magnetron sputtering principle, only need apply 200 and give first care of 400 v's direct current voltage on the cathode cylinder and can produce plasma, and plasma density and the plasma density that radio frequency coil produced are equivalent. A positive voltage is applied to the anode lead plate, part of electrons in the plasma are pulled to the anode lead plate, and part of electrons are emitted from an electron emission hole in the center of the anode lead plate, so that the generated electrons are more stable compared with a high-temperature filament, the electron direction is regular, the practical service life is long, the cleanness is continuous, and more importantly, compared with a plasma neutralizer excited by a radio frequency RF power supply in a current high-end foreign ion source, the performance of generated electron beam is equivalent, but the structure is simple, and the cost is greatly reduced. The problems of high cost of the plasma neutralizer, unstable electron generation of the filament type neutralizer, short continuous working time and pollution in the prior art are solved.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a schematic diagram of a prior art structure;

FIG. 2 is a schematic view of the magnetic field distribution of the present invention;

in the figure: 1. the plasma cathode comprises a cathode cylinder, 2, an anode leading disc, 3, a cooling cylinder, 4, a permanent magnet magnetic ring, 5, a cooling cavity, 6, an inlet, 7, an outlet, 8, an insulating ceramic ring, 9, a ceramic upper cover, 10, a stainless steel lower cover, 11, an air inlet, 12, an electron exit hole, a plasma chamber, b, an RF coil, c, a collecting electrode, d and a maintaining electrode.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive work, are related to the scope of the present invention.

As shown in fig. 1-2, the present embodiment provides a novel ion source plasma neutralizer, which includes a cathode cylinder 1, an anode lead disc 2, and a cooling cylinder 3 disposed outside the cathode cylinder 1, wherein a permanent magnet ring 4 is sleeved outside the cooling cylinder 3, an interval exists between the anode lead disc 2 and one end of the cathode cylinder 1, the other end of the cathode cylinder 1 is an air inlet end, the cooling cylinder 3 is provided with a cooling cavity 5, and an inlet 6 and an outlet 7 communicated with the cooling cavity 5, the anode lead disc 2 is positively charged, and the cathode cylinder 1 is negatively charged.

In the embodiment, a novel ion source plasma neutralizer is disclosed, which mainly comprises a cathode cylinder 1, a cooling cylinder 3 outside the cathode cylinder 1, a permanent magnet ring 4 outside the cooling cylinder 3, and an anode lead disc 2 (i.e. a sustain electrode), wherein a space is formed between the cathode cylinder 1 and the anode lead disc 2, an electric field is formed between the cathode cylinder 1 and the anode lead disc 2, the cooling cylinder 3 is sleeved outside the cathode cylinder 1, a gap is formed between the cooling cylinder 3 and the cathode cylinder 1, the cooling cylinder 3 is grounded, a cooling cavity 5 is arranged on the side wall of the cooling cylinder 3, an inlet 6 and an outlet 7 are communicated with the cooling cavity 5, the permanent magnet ring 4 is sleeved outside the cooling cylinder 3, the permanent magnet ring 4 forms a magnetic field inside the cathode cylinder 1, the cathode cylinder 1 is connected with negative electricity, and the anode lead disc is connected with positive electricity; an inlet 6 and an outlet 7 of the cooling jacket are communicated with a cooling medium to form circulating cooling so as to protect the permanent magnet ring on the outer side from high-temperature demagnetization; gas (argon gas is commonly used) is introduced into one end, far away from the anode guide disc 2, of the cathode cylinder 1, the argon gas is ionized under the combined action of a magnetic field in the cathode cylinder and an electric field formed by negative voltage of the cathode cylinder to form plasma, the plasma is kept in the cathode cylinder 1, electrons move towards the anode guide disc 2 under the action of the electric field formed by positive voltage of the anode guide disc, and partial electrons are emitted from the electron emitting holes to form electron beam current. The ions in the plasma move to the wall of the cathode tube 1 under the action of the cathode tube electric field, and the cathode tube collects the ions because the charges are absorbed by the ions. The ions moving toward the cylindrical wall cause the cylindrical wall to be sputtered, and since the cathode cylinder is cylindrical, the sputtered material moves toward the opposite side and is deposited. The sputtered portion of the wall of the tube is sputtered and deposited simultaneously, so that the wall of the tube is consumed at a slow rate and the cathode tube 1 can be used for a long time before it needs to be replaced. Meanwhile, the materials sputtered from the cylinder wall move linearly, are difficult to be emitted from the double-layer electron emission holes, pollution is avoided, and the cleanliness of the process cavity is guaranteed;

in the course of the work, at first to the inboard argon gas that lets in of cathode cylinder 1, then add the negative electricity for cathode cylinder 1, the argon gas ionizes under the combined action in the electric field that negative voltage formed of cathode cylinder and the magnetic field that the permanent magnetism magnetic ring produced, form stable plasma in cathode cylinder 1, then draw dish 2 for the positive pole and add the positive voltage, draw under the effect of dish 2 electric fields at the positive pole, electron draws dish 2 motion to the positive pole, and partial electron draws the electron emission hole outgoing at dish center through ceramic upper cover and positive pole, forms electron beam.

Compared with the prior art, in the prior art (as shown in fig. 1), by introducing argon into the plasma chamber a, in order to ionize the argon to form plasma, or exciting with high frequency or microwave, for example, using 13.56MHz radio frequency power supply, the RF coil b applies radio frequency electric field to the cylindrical collecting electrode c in the plasma chamber, the surface of the collecting electrode c forms radio frequency bias voltage, so that gas is ionized, ions approach to the collecting electrode, and electrons are emitted under the action of the maintaining electrode d, the cost of forming electron jet is high, extremely high voltage is required, even more than 2000v, the density of formed plasma is very low, the maintenance cost is also high after failure, otherwise, high direct current voltage (>2000 v) is required to excite to generate plasma, and the density of generated plasma is lower by an order of magnitude than that of plasma generated by the radio frequency coil, and the novel plasma source neutralizer of the ion source is added outside the cathode cylinder 1 through a permanent magnet, a magnetic field is formed inside the cathode cylinder 1 (plasma region), similar to the DC magnetron sputtering principle, only 200-400V DC voltage is applied to the cathode cylinder 1 to generate plasma, and the plasma density is equivalent to that generated by the RF coil. A positive voltage is applied to the anode lead disc 2, part of electrons in the plasma are pulled to the anode lead disc 2, part of electrons are emitted from an electron emission hole in the center of the anode lead disc 2, the generated electrons are more stable compared with a high-temperature filament, the density of the formed plasma is higher, the direction of the electrons is regular, the practical service life is long, the cleaning is continuous, more importantly, compared with a plasma neutralizer excited by a radio frequency RF power supply adopted by a current high-end electron source abroad, the performance is equivalent, the plasma neutralizer has the advantages of simple structure and low cost, and the problems that the cost of the plasma neutralizer in the prior art is high, the electrons of the ion source filament type neutralizer are unstable, the continuous working time is short and the plasma is polluted are solved.

Coolant is introduced into the cooling cavity 5.

In this embodiment, let in the coolant in cooling cavity 5, the coolant can be water or the high-efficient liquid that absorbs the heat, in maintaining the plasma in-process, the plasma can produce high temperature, high temperature can produce the weakening effect to the magnetic force of permanent magnetism magnetic ring 4, cooling cylinder 3 gives the coolant in cooling cavity 5 with the heat transfer of negative pole section of thick bamboo 1, the coolant takes the heat out, thereby avoid causing the weakening to the magnetic force of permanent magnetism magnetic ring 4, the life of equipment has been promoted.

The anode lead disc 2 is positively charged by 30-50V.

In this embodiment, the anode lead 2 is positively charged, and the positive charge is selected within a range of 30 to 50V, and the plasma state can be maintained, and the electrons can be ejected by attracting the electrons in the moving direction to form an electron jet.

The cathode cylinder 1 is connected with negative electricity of 200-400V.

In this embodiment, the cathode cylinder 1 is negatively charged, the range of the negative charge is 200-400V, the cathode cylinder 1 is made of high temperature resistant metal, such as titanium, the inside of the cathode cylinder 1 is a place for maintaining plasma, and the inside of the cathode cylinder 1 contains process gas (mostly argon) for forming plasma, and forms an orthogonal electric field and magnetic field.

Add insulating ceramic ring 8, ceramic upper cover 9 and stainless steel lower cover 10, ceramic upper cover 9 the one end of a negative pole section of thick bamboo 1 is located a negative pole section of thick bamboo 1 with between the positive pole draws the dish 2, insulating ceramic ring 8 with stainless steel lower cover 10 is followed the axial of a negative pole section of thick bamboo 1 sets gradually the other end of a negative pole section of thick bamboo 1.

In this embodiment, an insulating magnetic ring is installed at one end of the cathode cylinder 1, a ceramic upper cover 9 is installed on the cathode cylinder close to one end of the anode lead disc 2, a stainless steel lower cover 10 is also installed on the outer side of the insulating magnetic ring far away from one end of the anode lead disc 2, the insulating magnetic ring can play an insulating role between the cathode cylinder 1 and the stainless steel lower cover, and the ceramic upper cover 9, the stainless steel lower cover 10 and the cathode cylinder 1 form a relatively closed plasma region together.

The stainless steel lower cover 10 is provided with an air inlet 11.

In this embodiment, an air inlet is provided on the stainless steel lower cover 10, and gas (usually argon) is introduced into the cathode tube 1, so that plasma is generated by glow under the action of the electric field and the magnetic field.

The ceramic upper cover 9 and the anode lead disc 2 are both provided with an electron exit hole 12.

In this embodiment, the ceramic upper cover 9 and the anode lead 2 are both provided with electron exit holes 12, and under the action of an electric field formed by positive voltage of the anode lead by plasma in the cathode cylinder 1, electrons in the plasma are emitted from the ceramic upper cover 9 and the electron exit holes 12 of the anode lead 2, so as to form a directional emission electron beam.

The inlet 6 is arranged at one end far away from the anode lead disc 2, and the outlet 7 is arranged at the other end of the cooling cylinder 3.

In this embodiment, the inlet 6 on the cooling cylinder 3 is at the one end of keeping away from the anode lead plate 2, the outlet 7 is at the other end of the cooling cylinder 3, the coolant flow direction in the cooling cavity 5 is from bottom to top, and the inside coolant and heat can realize more sufficient heat exchange, thereby ensuring that the permanent magnet ring 4 is not weakened by the high temperature of the cathode cylinder 1.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a novel ion source plasma neutralizer, its characterized in that draws dish (2), sets up including a cathode cylinder (1), positive pole cooling cylinder (3) in a cathode cylinder (1) outside, cooling cylinder (3) outside cover is equipped with permanent magnetism magnetic ring (4), positive pole draw dish (2) with there is the interval in the one end of a cathode cylinder (1), the other end of a cathode cylinder (1) is the inlet end, be provided with on cooling cylinder (3) cooling cavity (5) and with import (6) and export (7) of cooling cavity (5) intercommunication, positive electricity is drawn to positive pole dish (2), a cathode cylinder (1) connects negative electricity.

2. The novel ion source plasma neutralizer according to claim 1, wherein coolant is introduced into the cooling cavity (5).

3. The novel ion source plasma neutralizer according to claim 1, wherein the anode lead plate (2) is positively charged by 30-50V.

4. The novel ion source plasma neutralizer according to claim 1, wherein the cathode cylinder (1) is negatively charged with 200-400V.

5. The novel ion source plasma neutralizer according to claim 1, wherein an insulating ceramic ring (8), a ceramic upper cover (9) and a stainless steel lower cover (10) are additionally arranged, the ceramic upper cover (9) is arranged at one end of the cathode cylinder (1) and is positioned between the cathode cylinder (1) and the anode guide disc (2), and the insulating ceramic ring (8) and the stainless steel lower cover (10) are sequentially arranged at the other end of the cathode cylinder (1) along the axial direction of the cathode cylinder (1).

6. The novel ion source plasma neutralizer according to claim 5, wherein the stainless steel lower cover (10) is provided with a gas inlet (11).

7. The novel ion source plasma neutralizer according to claim 5, wherein an electron exit hole (12) is provided on both the ceramic upper cover (9) and the anode lead plate (2).

8. The novel ion source plasma neutralizer according to claim 1, wherein the inlet (6) is disposed at an end remote from the anode lead plate (2) and the outlet (7) is at the other end of the cooling drum (3).