CN111029235A

CN111029235A - Structure of ion source head in ion implantation machine

Info

Publication number: CN111029235A
Application number: CN201911353080.8A
Authority: CN
Inventors: 谢石谦; 丁杰; 何春雷
Original assignee: Shanghai Huali Integrated Circuit Manufacturing Co Ltd
Current assignee: Shanghai Huali Integrated Circuit Manufacturing Co Ltd
Priority date: 2019-12-25
Filing date: 2019-12-25
Publication date: 2020-04-17
Anticipated expiration: 2039-12-25
Also published as: CN111029235B

Abstract

The invention discloses a structure of an ion source head in an ion injection machine table, which comprises an arc starting chamber, a reflecting electrode and a pure tungsten small baffle plate, wherein the arc starting chamber comprises a graphite end plate and a graphite cavity main body, a groove is formed in the graphite end plate, the graphite cavity main body is pressed on the pure tungsten small baffle plate and the graphite end plate, through holes are formed in the centers of the graphite end plate and the pure tungsten small baffle plate, a first insulating baffle plate is arranged between the pure tungsten small baffle plate and the graphite end plate, a second insulating baffle plate is arranged between the pure tungsten small baffle plate and the end part, close to the graphite end plate, of the graphite cavity main body, and through holes for the terminal part of the reflecting electrode to pass through are formed in the centers of the first insulating baffle plate and the second insulating baffle plate. The invention can effectively solve the problem that the repeller is communicated with the pure tungsten small baffle when peeling occurs, so that the repeller is communicated with the arc-starting chamber, thereby prolonging the service life of the ion source and the maintenance period of the machine.

Description

Structure of ion source head in ion implantation machine

Technical Field

The invention relates to the field of manufacturing of microelectronic and semiconductor integrated circuits, in particular to a structure of an ion source head in an ion implantation machine (VIISta Trident machine).

Background

Currently, the VIISta Trident machine is mainly used for the process of high-intensity implantation conditions in the ion implantation (implantation) process, and the machine is mainly divided into an ion source, a beam line portion, a target chamber and a terminal station. The ion source is where ions are generated, usually by electron impact on gas molecules or atoms. The ion source mainly comprises four parts, namely a gas box, an ion source head (source head), a high-voltage suction electrode and an ion source cavity (source chamber), wherein the ion source head comprises an Arc chamber (Arc chamber), an evaporator, a filament (filament) and a reflector (reflector), and the filament, a cathode and the reflector are arranged in the Arc chamber.

Fig. 1 shows the structure of an ion source head 100 for an ion implanter. As shown in fig. 1, the ion source head 100 includes an arc starting chamber 104 defining a predetermined space, a cathode 102 installed at one side of the arc starting chamber, a filament 101 installed in an inner space of the cathode 102, and a repeller 103 installed opposite to the cathode 102.

The filament 101 may be made of a high melting point metal (e.g., tungsten) and serves to emit thermal electrons to the outside when heated to a predetermined temperature by a current flowing from an externally connected power supply. The cathode 102 is spaced a distance from the filament 101. The cathode voltage is connected to the cathode 102 at a high potential and to the filament 101 at a low potential to form an electric field between the filament 101 and the cathode 102, by which thermal electrons are emitted from the filament 101. The thermal electrons are collected at the cathode 102 and are connected to the arc starting chamber 104 by a high potential of the arc starting voltage, and a low potential is connected between the cathodes 102 to form an electric field, so that electrons are emitted again from the surface of the cathode 102. Electrons are emitted toward the space defined by the arc starting chamber 104. A dopant gas and a carrier gas are introduced into the space through the gas inlet 105. The slit member 106 is disposed opposite the gas inlet. Ions are emitted through the slit member 106.

A power supply unit is connected to the arc starting chamber 104 to accelerate the electrons emitted from the cathode 102. The repeller 103 is mounted in relatively short circuit with the cathode 102 at one side of the arc starting chamber 104 and serves to reflect accelerated electrons emitted from the cathode 102, thereby distributing ions within a limited space. The

magnets

110a and 110b may be mounted around the arc starting chamber 104. The magnets may be electromagnets, and in the presence of a magnetic field, the lorentz force action allows accelerated motion electrons to move spirally within the arcing chamber 104. The helical motion of the electrons increases the probability that the electrons will collide with gas particles, achieving high ionization efficiency.

A slit member 106 through which ions are emitted may be provided on an upper surface of the arc starting chamber 104, and a gas inlet 105 may be formed opposite to the slit member 106.

As shown in fig. 2, the arc striking chamber 104 is a cavity made of graphite material, and includes a graphite end plate 1041 and a graphite cavity main body (not shown), and the graphite end plate 1041 is disposed at an end of the graphite cavity main body. As shown in fig. 3, the cross section of the graphite chamber body 1042 (i.e. the section parallel to the graphite end plate) is substantially "concave" and the top is formed with an arc-shaped groove, and the side of the graphite end plate 1041 facing the graphite chamber body 1042 is formed with a groove for accommodating the small pure tungsten baffle 107. Through holes are formed in the centers of the graphite end plate 1041 and the small pure tungsten baffle 107. The repeller 103 includes a reflecting portion and a terminal portion for increasing the chance of collision of electrons with gas molecules, sufficiently ionizing the gas molecules, and generating more ions. The terminal part of the repeller 103 passes through the through hole at the center of the graphite end plate 1041 and the small pure tungsten baffle 107, but the terminal part does not contact the graphite end plate 1041 and the small pure tungsten baffle 107.

The service life of the ion source head represents the shortest working life of the ion implanter, and the influencing factors are filament open (filament open), cathode short circuit (bais short), and Arc chamber short circuit (Arc short), wherein the Arc chamber short circuit accounts for the vast majority. The reason is that the implantation dosage and the implantation frequency of carbon C and germanium Ge in the ion implantation process are high, and these two elements are easy to form a viscous peeling phenomenon (peeling), and such conductive viscous debris can adhere to the arc-starting chamber to cause short circuit of the arc-starting chamber.

In the actual ion implantation process, the machine is shut down abnormally, and through research, a blanking phenomenon is easily caused between the repeller 103 and the small pure tungsten baffle 107 in the ion source head, so that the repeller 103 is conducted with the Arc starting chamber 104 to form an Arc voltage short circuit (Arc voltage short), and the machine is shut down. Under the condition, in order to solve the problem of machine halt, only the maintenance of the ion source can be carried out, which leads to the shortening of the maintenance period and the increase of the expenditure of the maintenance consumables, and the ion source can be produced again after being maintained for 24 hours, thus the normal running of the machine is blocked, and the reduction of the productivity is caused.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a structure of an ion source head in an ion implantation machine, which can solve the problem that the machine is shut down due to the occurrence of peeling of a reflecting electrode and a small pure tungsten baffle in the existing ion source head.

In order to solve the technical problem, the structure of the ion source head in the ion implantation machine table provided by the invention comprises an arc starting chamber, a reflector and a pure tungsten small baffle, wherein the arc starting chamber comprises a graphite end plate and a graphite cavity main body, a groove is formed in the graphite end plate, the graphite cavity main body is pressed on the pure tungsten small baffle and the graphite end plate, a first insulating baffle is arranged between the pure tungsten small baffle and the graphite end plate, a second insulating baffle is arranged between the pure tungsten small baffle and the end part, close to the graphite end plate, of the graphite cavity main body, and through holes for the terminal part of the reflector to pass through are formed in the centers of the first insulating baffle and the second insulating baffle.

The first insulating baffle is embedded in a groove of the graphite end plate, and a groove for accommodating the small pure tungsten baffle is formed in the first insulating baffle.

Further, the first insulating baffle comprises a top plate, a bottom plate, a front side plate, a rear side plate and a left side plate, the top plate, the bottom plate, the front side plate and the rear side plate are all perpendicular to the left side plate, and the left side plate, the top plate, the bottom plate, the front side plate and the rear side plate enclose a groove for containing the pure tungsten small baffle.

Preferably, the front side plate and the rear side plate of the first insulating barrier are further formed with outwardly extending tabs.

Wherein the shape of the second insulating baffle is the same as the shape of the end part of the graphite cavity main body close to the graphite end plate.

Wherein the second insulating baffle is only located in the portion of the graphite chamber body that contacts the small pure tungsten baffle.

Wherein the first insulating barrier is made of quartz or ceramic.

Wherein the second insulating barrier is made of quartz or ceramic.

And a gap is reserved between the outer wall of the terminal part of the reflection electrode and the wall of the through hole in the center of the first insulating baffle.

And a gap is reserved between the outer wall of the terminal part of the reflection electrode and the wall of the through hole in the center of the second insulating baffle.

The center of the through hole of the graphite end plate, the center of the through hole of the first insulating baffle, the center of the through hole of the pure tungsten small baffle and the center of the through hole of the second insulating baffle are on the same straight line.

Compared with the existing ion generating device of the ion implantation machine, the ion source head is improved, wherein the first insulating baffle is additionally arranged between the graphite end plate of the arc striking chamber and the pure tungsten small baffle, and the second insulating baffle is additionally arranged between the pure tungsten small baffle and the graphite cavity main body, so that the problem of conduction between the reflecting electrode and the arc striking chamber due to conduction between the reflecting electrode and the pure tungsten small baffle when peeling occurs can be solved, the real insulation between the reflecting plate and the pure tungsten small baffle is realized, the abnormal shutdown problem caused by short circuit of the arc striking chamber is effectively solved, and the service life of the ion source head and the maintenance period of the machine are prolonged.

Drawings

FIG. 1 is a schematic diagram of an ion source head in an ion implanter;

fig. 2 is an exploded view of the prior art ion source at the graphite end plate of the arc chamber;

FIG. 3 is a schematic structural view of a graphite chamber body of an arc chamber in an ion source head;

fig. 4 is an exploded view of the components at the graphite end plate of the arc chamber in the ion source head of the present invention.

Wherein the reference numerals are as follows:

100 is an ion source; 101 is a filament; 102 is a cathode; 103 is a reflecting electrode; 104 is an arc starting chamber; 1041 is a graphite end plate; 1042 is a graphite chamber body; 105 is a gas inlet; 106 is a slit member; 107 small pure tungsten baffles; 108 is a first insulating barrier; 109 is a second insulating baffle; 110a, 110b are magnets.

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the disclosure of the present specification, which is set forth in the following detailed description of the preferred embodiments of the invention and the accompanying drawings. The invention is capable of other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit of the present invention.

It should be noted that all directional indicators (such as upper, lower, left, right, front, back, top, bottom, inner and outer … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components in a specific posture, and if the specific posture is changed, the directional indicator is changed accordingly.

In the present invention, unless otherwise expressly stated or limited, the terms "connected," "secured," and the like are to be construed broadly, and for example, "secured" may be a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Example one

In this embodiment, the structure of ion source head in the ion implantation board, including the arc chamber, repeller 103 and the little baffle 107 of pure tungsten, the arc chamber includes graphite end plate 1041 and graphite chamber main part, the graphite end plate is formed with the recess, graphite chamber main part pressure equipment is in the little baffle of pure tungsten with on the graphite end plate, as shown in fig. 4, the little baffle 107 of pure tungsten with be equipped with first insulating baffle 108 between the graphite end plate 1041, the little baffle 107 of pure tungsten with graphite chamber main part is close to be equipped with second insulating baffle 109 between the tip of graphite end plate 1041, first insulating baffle 108 with the center department of second insulating baffle 109 all is formed with the through-hole that supplies the terminal part of repeller 103 to pass.

In the structure of the existing ion source head, the small pure tungsten baffle 107 is directly installed in the groove of the graphite end plate 1041, the graphite cavity body is pressed on the small pure tungsten baffle and the graphite end plate, when peeling occurs between the repeller and the small pure tungsten baffle, the repeller and the Arc-starting chamber are conducted to form an Arc-starting chamber short circuit Arc short. Because the small pure tungsten baffle is made of pure tungsten, the small pure tungsten baffle is high-temperature resistant, stable in physical property and free of ion absorption, and the small pure tungsten baffle is replaced by an insulating material, so that normal arcing cannot be realized in an arcing chamber. It is not possible to exchange a small baffle of pure tungsten for the insulating material.

In this embodiment, add first insulating barrier between the little baffle of graphite end plate and pure tungsten of arcing chamber, add second insulating barrier simultaneously between little baffle of pure tungsten and graphite chamber main part, the problem that the repeller switched on and lead to switching on between repeller and the arcing chamber with little baffle of pure tungsten when can solving peeling takes place like this, realize the real insulation of deflector and the little baffle of pure tungsten, thereby effectively solved the abnormal shut down problem that leads to because of arcing chamber short circuit Arc short, the life of ion source and the maintenance cycle of board have been prolonged.

After verification, after a first insulating baffle 108 and a second insulating baffle 109 are respectively added on two sides of the small pure tungsten baffle 107, the small pure tungsten baffle is obtained through multimeter test and is insulated from the outer side of the inner side of an arc striking chamber, the reflecting electrode is connected with the small pure tungsten baffle through a lead, the insulation between the reflecting electrode and the arc striking chamber is measured again, the ion source head is assembled, and the filament, the cathode and the arc striking chamber are all insulated through multimeter detection. The ion source head is arranged in the machine table, the machine is recovered after normal maintenance, the service life of the ion source head is tested to be longer than 250H, and the occurrence of the electric arc short circuit condition is effectively avoided.

Example two

On the basis of the first embodiment, the present embodiment further describes the structures of the first insulating barrier and the second insulating barrier.

As shown in fig. 4, the first insulating barrier 108 is embedded in the groove of the graphite end plate 1041, and the first insulating barrier 108 is formed with a groove for accommodating the small pure tungsten barrier 107.

As shown in fig. 4, the front and rear side plates of the first insulating barrier 108 are further formed with outwardly extending tabs to facilitate mounting of the first insulating barrier to the graphite end plate, i.e., the top plate, bottom plate, front side plate, rear side plate and left side plate of the first insulating barrier are located in the recess of the graphite cover plate and the two tabs are located outside the recess of the graphite cover plate.

As shown in fig. 4, the shape of the second insulating baffle is the same as the shape of the end portion of the graphite chamber main body close to the graphite end plate, that is, the second insulating baffle is a square plate with a U-shaped hole or an arc-shaped hole formed at the top.

Further, the second insulating baffle is only positioned in the part of the graphite cavity main body, which is in contact with the pure tungsten small baffle, namely the part of the graphite cavity main body, which is intersected with the pure tungsten small baffle.

Wherein the first insulating baffle is made of quartz or ceramic, preferably ceramic.

Wherein the second insulating baffle is made of quartz or ceramic, preferably ceramic.

The terminal part of the reflection electrode is not in contact with the through hole of the first insulating baffle and the through hole of the second insulating baffle, namely, a gap is reserved between the outer wall of the terminal part of the reflection electrode and the wall of the through hole at the center of the first insulating baffle and the wall of the through hole at the center of the second insulating baffle.

In this embodiment, utilize insulating baffle to keep apart between the little baffle of pure tungsten and the arcing chamber in the outside, the reflecting plate switches on with the little baffle of pure tungsten under the condition that pelling takes place, can not cause to switch on between reflecting plate and the arcing chamber yet, has just so prolonged the life-span of ion source, and insulating material does not in addition and ion direct contact, consequently can direct recycle.

The present invention has been described in detail with reference to the specific embodiments, which are merely preferred embodiments of the present invention, and the present invention is not limited to the above embodiments. Equivalent substitutions and modifications of the shape of the first insulating barrier and the shape of the second insulating barrier, etc., by those skilled in the art, without departing from the principles of the present invention, should be considered to be within the scope of the protection of the present invention.

Claims

1. The utility model provides a structure of ion source head in ion implantation board, includes the little baffle of arc-starting room, reflection utmost point and pure tungsten, the arc-starting room includes graphite end plate and graphite chamber main part, the graphite end plate is formed with the recess, graphite chamber main part pressure equipment is in the little baffle of pure tungsten with on the graphite end plate, the graphite end plate with the center department of the little baffle of pure tungsten all is formed with the through-hole, a serial communication port, the little baffle of pure tungsten with be equipped with first insulating barrier between the graphite end plate, the little baffle of pure tungsten with graphite chamber main part is close to be equipped with the second insulating barrier between the tip of graphite end plate, first insulating barrier with the center department of second insulating barrier all is formed with the through-hole that supplies the terminal part of reflection utmost point to pass.

2. The structure of an ion source head in an ion implanter as defined in claim 1, wherein the first insulating baffle is embedded in a groove of the graphite end plate, and the first insulating baffle is formed with a groove for receiving the small pure tungsten baffle.

3. The structure of an ion source head in an ion implantation machine according to claim 2, wherein the first insulating barrier comprises a top plate, a bottom plate, a front plate, a rear plate and a left plate, the top plate, the bottom plate, the front plate and the rear plate are all perpendicular to the left plate, and the left plate, the top plate, the bottom plate, the front plate and the rear plate enclose a groove for accommodating the small pure tungsten barrier.

4. The structure of an ion source head of an ion implanter as defined in claim 3, wherein the front plate and the back plate of the first insulating barrier are further formed with outwardly extending fins.

5. The structure of an ion source head in an ion implantation system as defined in claim 1, wherein the second insulating barrier has a shape substantially the same as an end of the graphite chamber body adjacent to the graphite end plate.

6. The structure of an ion source head in an ion implanter station as defined in claim 1, wherein the second insulating barrier is located only in the portion of the graphite chamber body that contacts the small pure tungsten barrier.

7. The structure of an ion source head in an ion implanter station as defined in claim 1, wherein the first insulating baffle is made of quartz or ceramic.

8. The structure of an ion source head in an ion implanter station as defined in claim 1, wherein the second insulating baffle is made of quartz or ceramic.

9. The structure of an ion source head in an ion implanter as defined in claim 1, wherein a gap is formed between an outer wall of a terminal portion of the repeller and a wall of the through hole at the center of the first insulating barrier.

10. The structure of an ion source head in an ion implanter as defined in claim 1, wherein a gap is formed between an outer wall of a terminal portion of the repeller and a wall of the through hole at the center of the second insulating barrier.

11. The structure of an ion source head in an ion implantation machine according to claim 1, wherein the center of the through hole of the graphite end plate, the center of the through hole of the first insulating barrier, the center of the through hole of the small pure tungsten barrier, and the center of the through hole of the second insulating barrier are on the same straight line.