Conductive beam optics including internal heating element
阅读说明:本技术 包含内部加热元件的导电束光学器件 (Conductive beam optics including internal heating element ) 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 艾立 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 electrostatic filter for delivering an ion beam to a wafer, the electrostatic filter comprising:
a housing; and
a plurality of conductive beam optics positioned within the housing, the plurality of conductive beam optics arranged around an ion beam line, wherein at least one of the plurality of conductive beam optics comprises an internal heating element.
2. The electrostatic filter for delivering an ion beam to a wafer of claim 1, wherein the internal heating element is a heat lamp, and wherein the at least one conductive beam optic further comprises:
a hollow shell surrounding the heating lamp; and
a conductor electrically connected to the heating lamp.
3. The electrostatic filter for delivering an ion beam to a wafer of claim 2, wherein the hollow shell is glassy carbon.
4. The electrostatic filter for delivering an ion beam to a wafer of claim 2, wherein the hollow shell is graphite.
5. The electrostatic filter for delivering an ion beam to a wafer of claim 2, further comprising an insulator disposed within each end of the hollow shell.
6. The electrostatic filter for delivering an ion beam to a wafer of claim 1, 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 farther away from the ion beam line than the set of entrance aperture electrodes and the set of ground electrodes.
7. The electrostatic filter for delivering an ion beam to a wafer of claim 6, wherein each of the set of high energy electrodes comprises an internal heating element.
8. The electrostatic filter for delivering an ion beam to a wafer of claim 1, further comprising an electrical system in communication with the plurality of conductive beam optics, the electrical system configured to independently supply voltage and current to each of the plurality of conductive beam optics.
9. The electrostatic filter for delivering an ion beam to a wafer of claim 8, the electrical system comprising a set of relays operable to control the voltage and the current to the internal heating element.
10. 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 along the ion beam line from the set of energetic electrodes, wherein the set of energetic electrodes are located farther from the ion beam line than the set of entrance aperture electrodes and the set of ground electrodes, and wherein at least one of the plurality of conductive beam optics comprises an internal heating element; and
an electrical system in communication with the electrostatic filter, the electrical system configured to supply voltage and current to the plurality of conductive beam optics.
11. The ion implantation system of claim 10, wherein the internal heating element is a heat lamp, and wherein the at least one of the plurality of conductive beam optics comprising the internal heating element comprises:
a hollow shell concentrically surrounding the heating lamp; and
a conductor in electrical connection with the heating lamp, wherein the conductor is part of the electrical system; and
an insulator disposed within an opening at each end of the hollow shell.
12. The ion implantation system of claim 10, wherein each of the plurality of conductive beam optics are connected in parallel to allow independent adjustment of the voltage and the current.
13. The ion implantation system of claim 10, 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.
14. The ion implantation system of claim 13, wherein the set of ground electrodes comprises a set of exit holes proximate to the outlet, wherein the set of exit holes define a maximum envelope of back sputtered material that travels from the wafer and through the outlet between the set of exit holes, wherein a first pair of exit holes of the set of exit holes are located proximate to a downstream end of the set of outlet plates, and wherein a second pair of exit holes of the set of exit holes are located proximate to an upstream end of the set of outlet plates.
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 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 electrostatic filter for delivering an ion beam to a wafer may comprise: a housing; and a plurality of conductive beam optics within the housing, the plurality of conductive beam optics arranged around the ion beam line, wherein at least one of the plurality of conductive beam optics comprises an internal heating element.
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. 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. At least one of the plurality of conductive beam optics includes an internal heating element.
In one or more embodiments, an ion implantation system may include an electrostatic filter for delivering an ion beam to a wafer. The electrostatic filter may include: a housing having an outlet proximate the wafer; and a plurality of conductive beam optics within the housing, the plurality of conductive beam optics 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 conductive beam optics may further comprise a set of ground electrodes located downstream of the set of high energy electrodes along the ion beam line. The set of high energy electrodes is positioned farther from the ion beam line than the set of entrance aperture electrodes and the set of ground electrodes, and wherein at least one of the plurality of conductive beam optics includes an internal heating element. The ion implantation system may further include an electrical system in communication with the electrostatic filter, the electrical system configured to independently supply voltage and current to 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-B 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. 4A is a perspective view of an electrical conduction beam optic including an internal heating element according to an embodiment of the present disclosure.
Fig. 4B is an end view of the beam-conducting optic shown in fig. 4A according to an embodiment of the present disclosure.
Fig. 5 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. 6 is a side cross-sectional view illustrating the assembly of FIG. 3 operating with a gas supply according to an embodiment of the present disclosure.
Fig. 7-8 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. 9 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 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 also prevents the high energy electrodes and holes from depositing back sputtered 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.
In an exemplary embodiment, the
As shown, there may be one or
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
The
Referring now to fig. 2A-B,
EPM40 also operates with one or more vacuum pumps 66 (fig. 1) to regulate the pressure of
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
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
As further shown, the
For example, during use, impact of the
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
Turning now to fig. 4A-4B, the conductive beam optics 70X including a heating element according to embodiments of the present disclosure will be explained in more detail. The conduction beam optics 70X may represent one or more of the conduction beam optics 70A-70P shown in fig. 3. In some embodiments, each of the conductive beam optics 70A-70P includes an internal heating element. In other embodiments, only one set of energetic electrodes 70C to 70F each have no internal heating element. In other embodiments, only one set of energetic electrodes 70C to 70F each contain an internal heating element.
As shown, representative conductive beam optics 70X can include an internal heating element 85 (e.g., a tubular quartz heating lamp), the
The
Turning now to FIG. 5, an
In some embodiments, at least one of the plurality of conductive beam optics 70A-70P includes an
In the non-limiting embodiment shown in FIG. 5, 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
In some embodiments, the accumulation of solid back sputtered 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
Turning now to FIG. 6, EPM40 may be cleaned in-situ during the cleaning mode. To accomplish the cleaning, an etchant gas (e.g., H) may be supplied from
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 detergents with chemically reactive species will be described herein, 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.
7-8, the operation of a set of relays 84A-84D within EPM40 according to embodiments 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
During beam setup, or during times when the implanter is idle, as shown in fig. 8, the high energy electrodes 70C through 70F may be connected to the
Referring now to fig. 9, a flow chart diagram of a
At
At
In some embodiments, block 105 of
At
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
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.
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