阅读说明：本技术 减少离子植入机中粒子的导电束光学器件 (Conductive beam optics for particle reduction in ion implanters ) 是由 常胜武 法兰克·辛克莱 亚历山大·利坎斯奇 克里斯多夫·坎贝尔 罗伯特·C·林德柏格 于 2019-01-22 设计创作，主要内容包括：本文提供减少离子植入机中粒子的方法。静电过滤器可包括壳体及位于壳体内的多个导电束光学器件。导电束光学器件围绕朝晶片引导的离子束线排列,且可包括靠近壳体的入口孔的入口孔电极。导电束光学器件还可包括沿着离子束线位于入口孔电极的下游的高能电极以及位于高能电极的下游的接地电极。高能电极被定位成比入口电极及接地电极更远离离子束线,从而使得高能电极在物理上被阻挡以免受从晶片返回的背溅射材料的包络撞击。静电过滤器还可包括用于独立地向导电束光学器件中的每一者递送电压及电流的电气系统。(Methods of reducing particles in an ion implanter are provided herein. The electrostatic filter may include a housing and a plurality of conductive beam optics positioned within the housing. The beam optics may be arranged around a beam line directed towards the wafer and may include an entrance aperture electrode proximate the entrance aperture of the housing. The conducting beam optics may further comprise a high energy electrode located downstream of the entrance aperture electrode along the ion beam line and a ground electrode located downstream of the high energy electrode. The high energy electrode is positioned further away from the ion beam line than the entrance and ground electrodes so that the high energy electrode is physically blocked from being struck by the envelope of back sputtered material returning from the wafer. The electrostatic filter may also include an electrical system for independently delivering voltage and current to each of the conductive beam optics.)

1. An ion implantation system, comprising:

an electrostatic filter for delivering an ion beam to a wafer, the electrostatic filter comprising:

a housing having an outlet proximate to the wafer; and

a plurality of conductive beam optics within the housing, the plurality of conductive beam optics arranged around an ion beam line, and the plurality of conductive beam optics comprising:

a set of inlet aperture electrodes proximate to the inlet apertures of the housing;

a set of high energy electrodes located along the ion beam line downstream of the set of entrance aperture electrodes; and

a set of ground electrodes located downstream of the set of energetic electrodes along the ion beam line, wherein the set of energetic electrodes are located further away from the ion beam line than the set of entrance aperture electrodes and the set of ground electrodes; and

an electrical system in communication with the electrostatic filter, the electrical system operable to supply voltage and current to the plurality of conductive beam optics.

2. The ion implantation system of claim 1, wherein each of the plurality of conductive beam optics are connected in parallel to allow independent adjustment of the voltage and the current.

3. The ion implantation system of claim 1, further comprising a set of exit plates extending from the housing, wherein the set of exit plates are oriented substantially parallel to a direction of travel of the ion beam, and wherein the set of ground electrodes comprises a set of exit apertures proximate the exit.

4. The ion implantation system of claim 3, wherein the set of exit apertures define a maximum envelope of back sputtered material that travels from the wafer and through the exit aperture between the set of exit apertures, and wherein a position of the set of high energy electrodes relative to the set of exit apertures prevents the maximum envelope of the back sputtered material from reaching the set of high energy electrodes.

5. The ion implantation system of claim 4, wherein a first pair of the set of exit apertures is positioned near a downstream end of the set of exit plates, and wherein a second pair of the set of exit apertures is positioned near an upstream end of the set of exit plates.

6. The ion implantation system of claim 1, further comprising a set of terminal electrodes positioned between the set of entrance aperture electrodes and the set of high energy electrodes.

7. The ion implantation system of claim 1, further comprising a set of relays operable to switch each of the set of high energy electrodes between a high voltage power supply and ground.

8. An energy purity module for delivering an ion beam to a workpiece, wherein the energy purity module comprises:

a housing having an outlet proximate the workpiece; and

a plurality of conductive beam optics positioned within the housing, the plurality of conductive beam optics comprising:

a set of inlet aperture electrodes proximate to the inlet apertures of the housing;

a set of high energy electrodes located along the ion beam line downstream of the set of entrance aperture electrodes; and

a set of ground electrodes located downstream of the set of energetic electrodes along the ion beam line, wherein the set of energetic electrodes are located further away from the ion beam line than the set of entrance aperture electrodes and the set of ground electrodes; and

an electrical system in communication with the plurality of electrical bundle optics, the electrical system operable to independently supply voltage and current to the plurality of electrical bundle optics.

9. The energy purity module of claim 8, further comprising:

a set of outlet apertures of the set of ground electrodes positioned proximate to the outlet; and

a set of outlet plates extending from the housing, wherein the set of outlet plates are oriented substantially parallel to the ion beam line, wherein a first pair of outlet apertures of the set of outlet apertures are positioned proximate a downstream end of the set of outlet plates, and wherein a second pair of outlet apertures of the set of outlet apertures are positioned proximate an upstream end of the set of outlet plates.

10. The energy purity module of claim 9, wherein the set of exit apertures define a maximum envelope of back sputtered material traveling from the workpiece and through the exit aperture between the set of exit apertures, and wherein the position of the set of high energy electrodes relative to the set of exit apertures minimizes the amount of back sputtered material reaching the set of high energy electrodes.

11. The energy purity module of claim 8, further comprising a set of terminal electrodes positioned between the set of inlet aperture electrodes and the set of high energy electrodes.

12. The energy purity module of claim 8, further comprising:

an internal heating element located within each of the set of high energy electrodes, the internal heating element operable to raise the temperature of each of the set of high energy electrodes; and

a set of relays operable to switch the internal heating element within each of the set of high energy electrodes between an on configuration and an off configuration.

13. A method of reducing particles in an ion implantation system, the method comprising:

arranging a plurality of pencil optics arranged around the ion beam line, wherein the plurality of pencil optics comprises:

a set of inlet hole electrodes disposed adjacent to the inlet hole of the housing;

a set of high energy electrodes disposed along the ion beam line downstream of the set of entrance aperture electrodes; and

a set of ground electrodes disposed downstream of the set of energetic electrodes along the ion beam line, wherein the set of energetic electrodes are positioned farther away from the ion beam line than the set of entrance aperture electrodes and the set of ground electrodes; and

an electrical system is enabled to independently supply voltage and current to the plurality of bundle optics.

14. The method of reducing particles in an ion implantation system of claim 13, further comprising:

a set of outlet holes providing the set of ground electrodes proximate to the outlet; and

providing a set of exit plates extending from the housing, wherein the set of exit apertures are oriented substantially parallel to the beamline,

wherein a first pair of outlet apertures of the set of outlet apertures is located proximate a downstream end of the set of outlet plates,

wherein a second pair of outlet apertures of the set of outlet apertures is located proximate an upstream end of the set of outlet plates, and

wherein the set of exit holes defines a maximum envelope of back sputtered material traveling from the wafer and through the exit holes.

15. The method of reducing particles in an ion implantation system of claim 14, further comprising:

adjusting a temperature of at least one of the plurality of conductive beam optics using an internal heating element; and

providing a set of relays operable to switch the internal heating element between an on configuration and an off configuration.

Technical Field

The present disclosure relates generally to ion implanters, and more particularly to conductive beam optics for improving performance and extending the life of components within a processing chamber by reducing particle accumulation.

Background

Ion implantation is a process of introducing dopants or impurities into a substrate by bombardment (bombardent). In semiconductor manufacturing, dopants are introduced to alter electrical, optical or mechanical properties. For example, dopants may be introduced into an intrinsic semiconductor substrate to alter the conductivity type and conductivity level of the substrate. In the fabrication of Integrated Circuits (ICs), precise doping profiles improve the performance of the IC. To achieve the desired doping profile, one or more dopants may be implanted in the form of ions at various doses and at various energy levels.

An ion implantation system may include an ion source and a series of beamline components. The ion source may include a chamber that generates the desired ions. The ion source may also include a power source and an extraction electrode assembly disposed adjacent the chamber. The beamline components may include, for example, a mass analyzer, a first acceleration or deceleration stage, a collimator, and a second acceleration or deceleration stage. Much like a series of optical lenses used to manipulate a beam, the beamline assembly filters, focuses, and manipulates an ion or ion beam of desired species, shape, energy, and other characteristics. The ion beam passes through the beamline assembly and may be directed toward a substrate or wafer mounted on a platen or chuck. The substrate may be moved (e.g., translated, rotated, and tilted) in one or more dimensions by a device sometimes referred to as a multi-axis rotating arm (ropot).

Ion implanters produce stable and well-defined ion beams for a variety of different ion species and extraction voltages. In using source gases (e.g. AsH)₃、PH₃、BF₃And other species) for several hours, the beam composition (beam consistency) eventually forms a deposit on the beam optics. Beam optics in the line-of-sight of the wafer may also be coated with residues from the wafer, including Si and photoresist compounds. These residues accumulate on the beamline components, causing spikes of Direct Current (DC) potential during operation (e.g., in the case of electrical bias components). Eventually the residue will flake off, thereby increasing the likelihood of particle contamination of the wafer.

One way to prevent material build-up from occurring is to intermittently replace the beamline components of an ion implanter system. Alternatively, the beamline assembly may be manually cleaned, including powering down the ion source and relieving the vacuum within the system. After replacement or cleaning of the wire harness assembly, the system is then drained and powered to an operational state. Thus, these maintenance processes can be very time consuming. In addition, the wire harness assembly cannot be used during the maintenance process. Thus, frequently maintaining processes may reduce the time available for integrated circuit production, thereby increasing overall manufacturing costs.

Disclosure of Invention

In view of the foregoing, provided herein are systems and methods for configuring a plurality of conductive beam optics within an Energy Purity Module (EPM) to reduce particles accumulated within the energy purity module. In one or more embodiments, an ion implantation system includes an electrostatic filter for delivering an ion beam to a wafer. The electrostatic filter may include: a housing having an outlet proximate to the wafer; and a plurality of conductive beam optics located within the housing. The plurality of conductive-beam optics are arranged around the ion beam line. The plurality of conductive beam optics may include: a set of inlet aperture electrodes proximate to the inlet apertures of the housing; and a set of high energy electrodes located along the ion beam line downstream of the set of entrance aperture electrodes. The plurality of conducting beam optics may also include a set of ground electrodes located downstream of the set of high energy electrodes along the ion beam line, wherein the set of high energy electrodes may be located further away from the ion beam line than the set of entrance aperture electrodes and the set of ground electrodes. The ion implantation system may also include an electrical system in communication with the electrostatic filter, the electrical system operable to supply voltage and current to the plurality of conductive beam optics.

In one or more embodiments, an Energy Purity Module (EPM) for delivering an ion beam to a workpiece may comprise: a housing having an outlet proximate the wafer; and a plurality of conductive beam optics located within the housing. The plurality of conductive beam optics may include: a set of inlet aperture electrodes proximate to the inlet apertures of the housing; and a set of high energy electrodes located along the ion beam line downstream of the set of entrance aperture electrodes. The plurality of conductive beam optics may also include a set of ground electrodes located downstream of the set of high energy electrodes along the ion beam line, wherein the set of high energy electrodes is located farther away from the ion beam line than the set of entrance aperture electrodes and the set of ground electrodes. The energy purity module may also include an electrical system in communication with the plurality of conductive beam optics, the electrical system operable to independently supply voltage and current to each of the plurality of conductive beam optics.

In one or more embodiments, a method for reducing particles in an ion implantation system may comprise: a plurality of conductive beam optics arranged around the ion beam line are arranged. The plurality of conductive beam optics may include: a set of inlet hole electrodes disposed adjacent to the inlet hole of the housing; and a set of high energy electrodes disposed along the ion beam line downstream of the set of entrance aperture electrodes. The plurality of conductive beam optics may also include a set of ground electrodes disposed downstream of the set of energetic electrodes along the ion beam line, wherein the set of energetic electrodes is positioned farther away from the ion beam line than the set of entrance aperture electrodes and the set of ground electrodes. The method may also include enabling an electrical system to independently supply voltage and current to each of the plurality of conductive beam optics.

Drawings

Fig. 1 is a schematic diagram illustrating an ion implantation system according to an embodiment of the present disclosure.

Fig. 2A-2B are semi-transparent isometric views illustrating components of the ion implantation system of fig. 1 according to an embodiment of the present disclosure.

Fig. 3 is a side sectional view illustrating the assembly shown in fig. 2 according to an embodiment of the present disclosure.

Fig. 4 is a side cross-sectional view illustrating the assembly of fig. 3 operating with an electrical system according to an embodiment of the present disclosure.

Fig. 5 is a side sectional view illustrating the assembly of fig. 3 operating with a gas supply according to an embodiment of the present disclosure.

Fig. 6-7 are side cross-sectional views illustrating the assembly of fig. 3 operating with a set of relays according to an embodiment of the present disclosure.

Fig. 8 is a flow chart illustrating an exemplary method according to an embodiment of the present disclosure.

The drawings are not necessarily to scale. The drawings are merely representative and are not intended to portray specific parameters of the disclosure. The drawings are intended to depict example embodiments of the disclosure, and therefore should not be considered as limiting the scope. In the drawings, like numbering represents like elements. In addition, certain elements in some of the figures may be omitted or not shown to scale for clarity of illustration. Also, for clarity, some reference numbers may be omitted in some of the drawings.

Detailed Description

Systems and methods according to the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the systems and methods are shown. The systems and methods may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the systems and methods to those skilled in the art.

For convenience and clarity, terms such as "top", "bottom", "upper", "lower", "vertical", "horizontal", "lateral", and "longitudinal" will be used herein to describe the relative placement and orientation of the various components and their constituent parts shown in the drawings. The terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.

As used herein, an element or operation recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural elements or operations, until such exclusion is explicitly recited. Furthermore, references to "one embodiment" of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

Methods of reducing particles in an ion implanter are provided herein. The electrostatic filter may include a housing and a plurality of conductive beam optics positioned within the housing. The beam optics may be arranged around a beam line directed towards the wafer and may include an entrance aperture electrode proximate the entrance aperture of the housing. The conducting beam optics may further comprise a high energy electrode located downstream of the entrance aperture electrode along the ion beam line and a ground electrode located downstream of the high energy electrode. The high-energy electrode is positioned farther from the ion beam line than the entrance electrode and the ground electrode, such that the high-energy electrode is physically blocked or shielded from being coated by the envelope (envelope) of back-sputtered material returning from the wafer. The electrostatic filter may also include an electrical system for delivering voltage and current to each of the conductive beam optics.

The electrostatic filter may be an energy purity module having a plurality of high energy electrodes "hidden" behind a grounded electrode so that back sputtered material cannot reach the high energy electrodes. In some embodiments, one or more of the conductive beam optics of the energy purity module include an internal heating element operable to raise the temperature thereof. The in-situ cleaning and chemical etching by the gas evolution in the EPM prevents the high energy electrode and the hole from depositing the back sputter material. Thus, the performance and accuracy of the ion implanter may be improved.

Referring now to fig. 1, an exemplary embodiment is shown illustrating an ion implanter or ion implantation system (hereinafter "system") 10 for delivering an ion beam to a wafer or workpiece and for performing plasma cleaning in situ on one or more components, such as, for example, a beam-conducting optics within an electrostatic filter. System 10 represents a process chamber that contains, among other components: an ion source 14 for generating an ion beam 18, an ion implanter, and a series of beamline components. The ion source 14 may include a chamber for receiving the gas stream 24 and generating ions. The ion source 14 may also include a power supply and extraction electrode assembly disposed near the chamber. The beamline assembly 16 may include, for example, a mass analyzer 34, a first acceleration or deceleration stage 36, a collimator 38, and an Energy Purity Module (EPM) 40 corresponding to the second acceleration or deceleration stage. Although described below with respect to the energy purity module 40 of the beamline assembly 16 for purposes of explanation, the embodiments described herein for performing in-situ plasma cleaning may also be applicable to different/other components of the system 10.

In an exemplary embodiment, the beamline assembly 16 may filter, focus, and manipulate ions or ion beams 18 having desired species, shape, energy, and other characteristics. The ion beam 18 passing through the beamline assembly 16 may be directed toward a substrate mounted on a platen or chuck within the process chamber 46. The substrate may be moved (e.g., translated, rotated, and tilted) in one or more dimensions. The ion beam 18 travels along an ion beam line corresponding to an approximate center of the illustrated ion beam 18.

As shown, there may be one or more feed sources 28 operable with the chamber of the ion source 14. In some embodiments, the material provided from the feed source 28 may include source material and/or other materials. The source material may contain dopant species that are introduced into the substrate in ionic form. Meanwhile, the other materials may include a diluent that is introduced into the ion source chamber of the ion source 14 along with the source material to dilute the concentration of the source material in the chamber of the ion source 14. The other materials may also include a cleaning agent (e.g., an etchant gas) that is introduced into the chamber of the ion source 14 and transported within the system 10 to clean one or more beamline components 16.

In various embodiments, different substances may be used as source materials and/or the other materials. Examples of the source material and/or the other material may include an atomic substance or a molecular substance containing boron (B), carbon (C), oxygen (O), germanium (Ge), phosphorus (P), arsenic (As), silicon (Si), helium (He), neon (Ne), argon (Ar), krypton (Kr), nitrogen (N), hydrogen (H), fluorine (F), and chlorine (Cl). One of ordinary skill in the art will recognize that the above listed materials are non-limiting and that other atomic or molecular materials may also be used. Depending on the application, the substance may act as a dopant or the other material. In particular, a substance used as a dopant in one application may be used as another material in another application, and vice versa.

In an exemplary embodiment, the source material and/or other materials are provided in a gaseous or vapor form into an ion source chamber of the ion source 14. If the source material and/or other materials are in a non-gaseous or non-vaporous form, a vaporizer (not shown) may be provided near the feed source 28 to convert the materials into a gaseous or vaporous form. To control the amount and rate at which source material and/or other materials are provided into the system 10, a flow rate controller 30 may be provided.

The energy purity module 40 is a beamline component operable to independently control deflection, deceleration, and focusing of the ion beam 18. In one embodiment, the energy purity module 40 is a Vertical Electrostatic Energy Filter (VEEF) or an Electrostatic Filter (EF). As will be described in more detail below, energy purity module 40 may include the following electrode configurations: the electrode configuration includes a set of upper electrodes disposed above the ion beam 18 and a set of lower electrodes disposed below the ion beam 18. The set of upper electrodes and the set of lower electrodes may be stationary and have fixed positions. The potential difference between the set of upper electrodes and the set of lower electrodes may also be varied along the central ion beam trajectory to reflect the energy of the ion beam at each point along the central ion beam trajectory to independently control deflection, deceleration, and/or focusing of the ion beam.

Referring now to fig. 2A-2B, energy purity module 40 according to an exemplary embodiment will be explained in more detail. As shown, EPM40 includes EPM chamber 50 extending above EPM40 and partially enclosing EPM 40. EPM chamber 50 is operable to receive a gas and generate a plasma therein. In one embodiment, as shown in fig. 2A, the EPM chamber 50 may receive the gas stream 24 from the ion source 14 through a sidewall 54 at a gas inlet 52 (fig. 1). In another embodiment, as shown in fig. 2B, EPM chamber 50 may receive gas stream 56 at gas inlet 58 through a top section 60 of EPM chamber 50. The gas 56 may be supplied from a supplemental gas source 62 separately from the gas flow 24 from the ion source 14. In an exemplary embodiment, the injection rate at which gas 56 is injected into EPM chamber 50 may be controlled by a flow controller 64 (e.g., a valve).

EPM40 also operates with one or more vacuum pumps 66 (fig. 1) to adjust the pressure of EPM chamber 50. In the exemplary embodiment, vacuum pump 66 is coupled to process chamber 46 and regulates a pressure within EPM chamber 50 through one or more flow paths 68. In another embodiment, EPM40 may include one or more additional pumps that are more directly coupled to EPM chamber 50.

Referring now to fig. 3, an exemplary embodiment is shown demonstrating the structure and operation of EPM40 according to the present disclosure. As shown, the EPM40 may include a plurality of conductive beam optics 70A-70P (e.g., a plurality of graphite electrode rods), which are disposed along opposite sides of the ion beam 18, 70A-70P. The ion beam 18 is delivered through the EPM40, enters the entrance aperture 53 of the housing 49, and exits at the exit 47 to impact with the wafer 57 and the dose cup 59. As shown, the plurality of beam optics 70A-70P provide spaces/openings to allow the ion beam 18 (e.g., a ribbon beam) to pass therethrough. As described above, vacuum pump 66 may be connected directly or indirectly to housing 49 for regulating the ambient pressure therein.

In an exemplary embodiment, the conductive beam optics 70A-70P include a plurality of pairs of conductive pieces (conductive pieces) electrically coupled to each other. Alternatively, the beam optics 70A-70P may be a series of unitary structures that each include an aperture through which the ion beam passes. In the illustrated embodiment, the upper and lower portions of each electrode pair may have different electrical potentials (e.g., located in separate conductive members) to deflect an ion beam passing therethrough. Although the plurality of conducting beam optics 70A-70P are shown as including sixteen (16) elements, a different number of elements (or electrodes) may be utilized. For example, the configuration of the conduction beam optics 70A-70P may utilize a range of three (3) electrode sets to ten (10) electrode sets.

In one non-limiting embodiment, the conduction beam optics 70A-70P may include a set of entrance aperture electrodes or aperture terminals 70A-70B proximate the entrance aperture 53 of the housing 49. Downstream of the set of inlet aperture electrodes 70A-70B is a set of energetic electrodes 70C-70F. Between the set of inlet aperture electrodes 70A-70B and the set of high energy electrodes 70C-70F may be a set of terminal electrodes 70G-70H. The plurality of conduction beam optics 70A-70P may also include a set of ground electrodes 70I-70P, where ground electrodes 70M, 70N, 70O, and 70P may represent a set of exit apertures positioned proximate to exit aperture 47. As shown, the set of energetic electrodes 70C-70F are positioned farther from the ion beam 18 than the set of entrance aperture electrodes 70A-70B and the set of ground electrodes 70I-70P.

As further shown, the housing 49 may include a set of outlet plates 45 extending from the housing 49. In some embodiments, the set of exit plates 45 are each oriented substantially parallel to the direction of travel of the ion beam 18. As shown, a first pair of outlet apertures (e.g., ground electrodes 70O and 70P) are positioned proximate the downstream end 51 of the set of outlet plates 45. A second pair of outlet holes, such as ground electrodes 70M and 70N, are positioned proximate the upstream end 41 of the set of outlet plates 45. The first and second pairs of exit apertures are operable to deliver the ion beam 18 to the wafer 57 and control the bounce back from the wafer 57 into the material within the EPM40 along the direction of the ion beam 18.

For example, during use, impact of the ion beam 18 against the wafer 57 may produce material that tends to travel upstream along the ion beam 18 and into the EPM 40. The set of exit apertures 70M to 70P define a maximum envelope 61 of back sputtered material between the set of exit apertures 70M to 70P and an actual envelope 63 of back sputtered material that travels from the wafer 57 and through the exit 47. In some embodiments, the maximum envelope 61 is defined by the area within the EPM40 between the exit apertures 70O and 70P and between the ground electrodes 70K and 70L. The actual envelope 63 may be defined by an upper boundary/edge and a lower boundary/edge of the ion beam 18, e.g., proximate the exit 47 of the housing 49.

As shown, the location of the set of energetic electrodes 70C-70F relative to the set of exit apertures 70M-70P and ground electrodes 70I, 70J, 70K, and 70L prevents both the maximum envelope 61 of back sputtered material and the actual envelope 63 of back sputtered material from reaching the set of energetic electrodes 70C-70F. In other words, the set of energetic electrodes 70C-70F are positioned away from the ion beam 18 so as to be hidden or blocked behind the set of exit apertures 70M-70P and the ground electrodes 70I, 70J, 70K, and 70L.

Turning now to FIG. 4, an electrical system 65 in communication with EPM40 according to an embodiment of the present disclosure will be set forth in more detail. As shown, the electrical system 65 is operable to supply voltage and current to each of the plurality of conductive beam optics 70A-70P. In some embodiments, the plurality of conductive beam optics 70A-70P are each connected in parallel via the electrical system 65 to allow independent adjustment of voltage and current. In some embodiments, the electrical system 65 may include a first power source 67 (e.g., a terminal) and a second power source 69 (e.g., ground). The first and second power supplies 67 and 69 are operable to deliver a high voltage (e.g., 200V) to the plurality of conductive beam optics 70A-70P. More specifically, the first power supply 67 may be electrically connected with the set of inlet aperture electrodes 70A-70B and the set of terminal electrodes 70G-70H via a first electrical path 73. Meanwhile, a second power source 69 may be connected with each of the set of energetic electrodes 70C-70F and each of the set of grounded electrodes 70I-70P via a second electrical path 75. The term "energetic electrode" as used herein refers to an electrode that receives a high voltage from either the first power source 67 or the second power source 69.

In some embodiments, at least one of the plurality of conductive beam optics 70A-70P includes an internal heating element operable to raise its temperature. For example, the internal heating element 55 may be located within one or more of the set of inlet hole electrodes 70A-70B and within one or more of the set of terminal electrodes 70G-70H. An internal heating element 55 may also be located within each of the set of ground electrodes 70I-70P. As shown, the internal heating element 55 can be powered via a third electrical path 77 and a fourth electrical path 79. In some embodiments, the internal heating element 55 may be a quartz heating lamp buried within each respective electrode to evaporate the solid back sputtered material 78 into gaseous form to be pumped out of the EPM 40.

In the non-limiting embodiment shown in FIG. 4, four (4) high energy electrodes 70C through 70F are provided. The energetic electrodes 70C to 70F are positioned "hidden" behind the set of grounded electrodes 70I to 70P, thereby preventing the energetic electrodes 70C to 70F from splashing and coating of the back sputtered material within the maximum envelope 61 and/or the actual envelope 63. The back sputtering material is stopped and collected by the set of inlet hole electrodes 70A to 70B, the set of terminal electrodes 70G to 70H, and the set of ground electrodes 70I to 70P. A heating element buried within one or more of the set of inlet aperture electrodes 70A-70B, the set of terminal electrodes 70G-70H, and/or the set of ground electrodes 70I-70P may evaporate the solid back-sputtered material 78 into gaseous form to be pumped out of the EPM 40.

In some embodiments, solid back splashThe accumulation of shot material may be more severe, for example, when carborane, SiF, is used₄Or GeF₄As a source material. To prevent excessive accumulation, the EPM40 of the present disclosure can operate in two modes: a treatment mode and a cleaning mode. During the processing mode, the EPM40 may operate normally to process the ion beam 18. During the cleaning mode, EPM40 may be cleaned in situ. In one non-limiting embodiment, a second voltage and a second current may be supplied to the conductive beam optics 70A-70P of the EPM 40. The conductive beam optics 70A-70P may be electrically driven in parallel (e.g., individually) or in series to enable uniform and/or independent cleaning thereof. The second voltage and the second current may be supplied by the first power supply 67.

Turning now to fig. 5, EPM40 may be cleaned in-situ during the cleaning mode. To accomplish the cleaning, an etchant gas (e.g., H) may be supplied from gas supply 81 at a selected flow rate/injection rate₂Or O₂) Introduced into EPM 40. In an exemplary embodiment, gas supply assembly 81 is a gas evolving device including a conduit with a plurality of holes formed therein to allow distribution of etchant gases within EPM 40. For example, 1 standard cubic centimeter per minute (SCCM) to 5 standard cubic centimeters per minute of gas (e.g., O) may be delivered by the gas emitting device₂Or H₂) Introduced into the EPM chamber. The gas chemically etches away deposits of back sputtered material 78 from the set of inlet aperture electrodes 70A-70B, the set of terminal electrodes 70G-70H, and the set of ground electrodes 70I-70P. In other non-limiting examples, the etchant gas can be introduced at a flow rate of about 25 SCCM to about 200 SCCM. In one embodiment, the etchant gas may be introduced at about 50 SCCM to about 100 SCCM to maintain a high pressure flow around the beam optics 70A-70P.

Various substances can be introduced as a cleaner of the etchant gas. The cleaning agent may be an atomic or molecular substance containing a chemically reactive substance. These species, when ionized, may chemically react with deposits accumulated on one or more of the beam optics 70A-70P. Although it will be described hereinDetergents with chemically reactive species, but this disclosure does not preclude the use of chemically inert species. In another embodiment, the cleaning agent may contain heavy atomic species to form ions having high atomic mass units (amu) upon ionization. Non-limiting examples of the cleaning agent may include atomic or molecular species containing H, He, N, O, F, Ne, Cl, Ar, Kr, and Xe, or combinations thereof. In one embodiment, NF₃、O₂Or Ar and F₂Mixtures of (a) or combinations thereof may be used as the cleaning agent.

The composition of the etchant gas may be selected to optimize chemical etching based on the composition of the deposits formed on the conductive beam optics 70A-70P. For example, fluorine-based plasma may be used to etch the composition of the beam containing B, P and As, while oxygen-based plasma may be used to etch the photoresist material. In one embodiment, the addition of Ar or other heavy species to the plasma mixture increases ion bombardment, thereby increasing the removal rate of deposits from the conductive beam optics 70A-70P when a chemically enhanced ion sputtering process is used. The plasma or ion bombardment also causes heating of the surface to aid in the chemical etch rate and to aid in stirring the surface deposits from the conductive beam optics 70A through 70P.

Turning now to fig. 6-7, the operation of a set of relays 84A-84D within EPM40 according to an embodiment of the present disclosure will be explained in more detail. As shown, the EPM40 may include the set of relays 84A-84D, the set of relays 84A-84D being operable to switch each of the set of energetic electrodes 70C-70F between the high voltage first power supply 67 and the second power supply 69 (ground). In the illustrated configuration, the inner heating elements 55 may be buried within the energetic electrodes 70C-70F. During ion implantation, as shown in fig. 6, the energetic electrodes 70C to 70F are connected to the high voltage power supply 67, and the internal heating element 55 is turned off.

During beam setup, or during times when the implanter is idle, as shown in fig. 7, the high energy electrodes 70C to 70F may be connected to a second power supply 69 and the internal heating element 55 may be turned on. In some embodiments, the energetic electrodes 70C to 70F are maintained above 200 ℃ during implantation to ensure that the energetic electrodes 70C to 70F are protected from deposition due to condensation of the gaseous back sputtered material. The in situ cleaning and chemical etching by the gas supply assembly 81 within the EPM40 prevents the high energy electrodes 70C-70F and the exit holes 70M, 70N, 70O, and 70P from depositing back sputtered material. Thus, the performance and accuracy of the ion implanter may be improved.

Referring now to fig. 8, a flow chart diagram of a method 100 of reducing particles in an ion implanter is shown, in accordance with an embodiment of the present disclosure. The method 100 will be explained in connection with the representations shown in fig. 1 to 7.

At block 101, the method 100 may include providing a set of inlet aperture electrodes disposed proximate to an inlet aperture of a housing of an EPM. In some embodiments, the EPM comprises a plurality of conducting beam optics comprising the set of entrance aperture electrodes. In some embodiments, the plurality of conductive beam optics comprises a plurality of electrode rods.

At block 103, the method 100 may include providing a set of high energy electrodes disposed along the beamline downstream of the set of entrance aperture electrodes. At block 105, the method 100 may include providing a set of ground electrodes disposed downstream of the set of energetic electrodes along the ion beam line, wherein the set of energetic electrodes are positioned farther away from the ion beam line than the set of entrance aperture electrodes and the set of ground electrodes.

In some embodiments, block 105 of method 100 may include providing a set of exit apertures of the set of ground electrodes proximate the exit, and providing a set of exit plates extending from the housing, wherein the set of exit apertures are oriented substantially parallel to the beamline. Block 105 of method 100 may also include positioning a first pair of outlet holes of the set of outlet holes near a downstream end of the set of outlet plates, wherein a second pair of outlet holes of the set of outlet holes are positioned near an upstream end of the set of outlet holes. The set of exit holes can define an envelope of back sputtered material that travels from the wafer and then through the exit holes.

At block 107, the method 100 may include enabling an electrical system to independently supply voltage and current to each of the plurality of conductive beam optics. In some embodiments, a first voltage and a first current are supplied to the plurality of beam-conducting optics during a processing mode. In some embodiments, the first voltage and the first current are supplied by a Direct Current (DC) power supply. In some embodiments, the method 100 further comprises switching from the treatment mode to the cleaning mode. In some embodiments, block 107 includes automatically switching from the processing mode to the cleaning mode if a predetermined threshold (e.g., a maximum acceptable number of beam glitches) is reached.

During the cleaning mode, a second voltage and a second current may be supplied to the conductive beam optics. In some embodiments, a second voltage and a second current are applied to the conductive beam optics to generate the plasma. In some embodiments, the second voltage and the second current are supplied by a Direct Current (DC) power supply or a Radio Frequency (RF) power supply.

At block 109, the method 100 may include supplying an etchant gas and/or adjusting a temperature of one or more of the plurality of conductive beam optics to reduce particles in the ion implanter and enable etching. In some embodiments, the injection rate of the etchant gas is adjusted. In some embodiments, the composition of the etchant gas is selected based on the composition of the deposits formed on the surface of the component to optimize etching of the component. In some embodiments, at least one of the plurality of electrical bundle optics comprises an internal heating element operable to raise the temperature thereof.

In view of the foregoing, at least the following advantages are achieved by the embodiments disclosed herein. In a first advantage, EPM reduces particles by eliminating or greatly reducing the deposition of back-sputtered material onto EPM electrodes and holes, thereby improving device yield and productivity of the ion implanter. In a second advantage, the EPM may include only four (4) high energy electrodes hidden behind the ground electrode and the holes, thereby preventing the high energy electrodes from splashing and coating with the back sputtered material. The back sputtered material is stopped and collected by the ground electrode/hole and the terminal electrode/hole. In a third advantage, the one or more conductive beam optics may include heat lamps buried inside to evaporate the back sputtered material into gaseous form to be pumped out of the EPM. In addition to the hidden high energy electrode, an automated and in situ cleaning mechanism helps keep all EPM electrodes and holes free of deposited back sputtered material during implantation.

While certain embodiments of the disclosure have been set forth herein, the disclosure is not to be limited thereto, as the scope of the disclosure is as broad in scope as the art will allow and as the specification may suggest. The above description is therefore not to be taken in a limiting sense. Other modifications will occur to those skilled in the art that are within the scope and spirit of the appended claims.